Pattern

Ok, I interpret this question as why Feruchemical ability is needed to access feruchemical power to compound. Upon thinking about it again, the ability should not be necessary to get f-power out of f-charged, unkeyed metalminds while burning them allomantically. Compounding, though, I interpret to be a bit more. You get the power out of the metal magnified (somewhere it is said tenfold), use some as you see fit and use the excess to refill another metalmind, so you get basically limitless f-charge. The limiting resource is the availability of the metal. To do this, you need not only be able to get f-power out of the metalmind, but also the ability to fill a metalmind - which is Feruchemical ability. This should be possible for anyone with Terris blood, according to VenDell - but again, be careful, he might be exaggerating. The Southern Medallions consist of a combination of two or even three unkeyed metalminds, one of them I think being an unkeyed nicrosilmind with stored Investiture, giving anyone who wears them the corresponding ability, depending on with what it is filled. I didn't find a really convincing theory (convincing for me) on creating the Medallions and their working mechanism, but what they effectively do seems clear: They grant anyone who wears them one or more feruchemical abilities. So with them, also a southern allomancer (very rare) would be able to compound.

Change "unkeyed" to "keyed to himself". An allomancer with a trace of Terris blood is supposed to be able to use an unkeyed metalmind, if VenDell is correct. So being an allomancer this should also allow him to compound since the feruchemical properties are the same as if the metalmind were keyed to himself. He should be able to compound then, except something else prevents this. This isn't implied by the 2 WoBs we were discussing above though, but by information from BoM - which might come from an unreliable narrator. I would guess though that those theories from VenDell are not so far off, so we all get a teaser for technological advance in the last book of era 2 and in era 3. Southern Medallions probably will give a boost in development of Allotechemy (Allomancy + technology + Feruchemy).

@The One Who Connects No reason to be sad, I forgot to explain that particular line which you understood correctly. Not (A OR B ) is equivalent to (Not A) AND (Not B), according to DeMorgans laws.

The Logical puzzle is just logic, using boolean algebra on the statements. "Implies" is not the same as equals. Every statement can take the values "true" and "false". My statement is: IF you burn metal AND no power is obtained, THEN it can only be from burning the unkeyed metalmind. This explicitly does not mean, that burning an unkeyed metalmind yields no power! That would be incorrect logic. Even the fact that burning metal has to give some form of power (because the burning is the result of accessing power) does not make the statement untrue: the boolean variable (Burn metal and no power obtained) then has the value (false) and from false anything can be implied. I see that my try in logical deduction led to more confusion than it helped, sorry for that. Clarifications for the logic part: "Misting is not burning unkeyed metalmind" means "Misting is burning keyed to self" OR "Misting is burning keyed to another". Ok, I try to write this again with words for better understanding, can't guarantee it will get better. WoBs gives us: IF a Misting burns a metalmind keyed to himself, THEN he will get Feruchemical Power (A => FP) IF a Misting burns a metalmind keyed to another, THEN he will get Allomantical Power, the Feruchemical charge is destroyed in the process (C => AP) I tried to come to a conclusion B => XYZ, but was not successful. In the next step I used Transposition(logic) (p => q) <=> (!q => !p) [in words: "IF p is true THEN q is true" is equivalent to "IF q is false, THEN p is false" !(B) = A or C means that the statement "Misting does not burn unkeyed metalmind (AND Misting burns some metalmind, as in assumption)" is the same as the statement "Misting burns metalmind keyed to self (A) OR Misting burns metalmind keyed to another". This implies from WoBs (bold statements): Feruchemical Power is released OR Allomantic Power is released. Using Transposition on that expression yields the final line. Addition due to @The One Who Connects answer: (! B = A OR C => FP OR AP ) (Transposition) <=> (! (FP OR AP) = !(!B ) = B (! (FP OR AP) = !FP AND !AP is obtained via De Morgan's Theorem, !(!B ) = B is double negation. The last line in words is IF a misting burns metal (assumtion) AND no power (not FP and not AP) is obtained, THEN the misting burns an unkeyed metalmind. (!AP AND !FP) => B That however does not say, that this can occur. It is perfectly possible, that burning metal and obtaining no power is impossible (except aluminium gnats, which we excluded). One could try to deduce something without the assumption that something is burnt at all, but that would probably allow even less conclusions. I hope the "logic puzzle" in words is better comprehendable, though the result is still a non-result. It doesn't allow me to draw the kind of conclusion I wanted to be able to draw. That done, I claim to have to cognitive power of CONFUSION...more of that can be found at https://en.wikipedia.org/wiki/Paradoxes_of_material_implication and related pages ;-) Meanwhile sitting on the train I dug into VenDell. The kandra are experimenting. If the information VenDell gives is correct, it means that nearly any Northern Scadrian (everybody with a bit of Terris blood) could use an unkeyed metalmind. BAM. That would also include our misting we want to be able to compound. So the burned metal would give the F-power. I leave the credibility of VenDell to you, he is trying to convince Wax to go on a treasure hunt after all and might be exaggerating (though I don't believe he is, just that it could be). @8bitBob I am fairly certain that our interpretations of Identity are the same or nearly the same. I got the impression that you misunderstood me. @The One Who Connects elaborated my point of view much better than I am able to.

I feel free to reuse your quote. The last two sentences are making the quote ambiguous again. Probably in 2009 the concept of unkeyed metalminds was not an issue. The question still is: Do you need Identity (spiritual connection) to access the feruchemical charge or is it sufficient to have an unkeyed metalmind to allomantically release the feruchemical charge (so it's not blocked). For Feruchemists it's just the lack of Identity-lock that is sufficient, but is it also for an Allomancer? It's probably the easiest solution to say "Yes, as long as something is not blocked, it's available". The easiest solution is not always the right one, though. Once again I am brought back to hypothetical Miles who would be able to use the healing power stored in the goldmind - and now I reformulate it to post BoM terminology - because the charge was stored with his Identity. The fact that the f-charge was stored with his Identity is given as the reason for the described mechanism to work. Storing an attribute in a metalmind without putting aside one's Identity into another metalmind would create some kind of Spiritual connection between Feruchemist and metalmind (not to be confused with the feruchemical power Connection). So lets apply some logic and see where it leads us. Problem is, a feruchemical charge can have three states so lets define three statements A: Misting burns F-charge keyed to himself. B: Misting burns unkeyed F-charge. C: Misting burns F-charge keyed to another person. FP: Feruchemical Power is set free AP: Allomantical Power is set free Assume a Misting IS burning a metalmind (leave out aluminium). ! denotes logical NOT; <=> is equivalency, => denotes implication (A => FP) <=> (!FP =>!A) bold: statements from WoBs (C => AP) <=> (!AP => !C) (! B = A OR C => FP OR AP ) <=> (! (FP OR AP) = !FP AND !AP => !(!B ) = B So if you see a Misting burning a metalmind without effects, he must be burning an unkeyed metalmind. That however does NOT say, that burning an unkeyed metalmind does give no effect. Feel free to play around with this a bit more, my time today is running out unfortunately ;-(

Identity is the difference between being able to use the charge or not: A keyed metalmind cannot be used by another ferring lacking the right Identity. An unkeyed metalmind can be used by any fering. It would be an elegant symmetry if you could use the keyed charge yourself even if you didn't have the ability at that time (anymore). You had the ability before, so the Identity doesn't give you an ability itself but the charge which has a spiritual connection to you still works for you. This spiritual connection is used as an explanation for the examples to work, so we shouldn't just ignore it and treat unkeyed metalminds the same as keyed. Here a WoB about the metalmind altering the magic (Spoiler tags for space) "The other place" is obviously the Spiritual Realm - or on Sel the Cognitive Realm. Here again both powers are needed for the compounding to work. Though it's ambiguous, not treating the possibility of unkeyed metalminds that could be burned. So here might be an indication that above theory might actually work (not what I intended to work out, but there it is). IF the compounded metalmind alone determines that the power of Feruchemy is boosted from the SR, then it would be possible to access that power from burning an unkeyed metalmind. Classical compounding is feruchemy fuelled by allomancy, there is WoB to be a way to use compounding the other way around, to fuel Allomancy using stored feruchemical attributes. Burning an unkeyed metalmind and obtaining the f-power could be this. It still does not feel balanced though. The misting is lacking the sDNA to use the f-power in any controlled way. The misting could control the release of f-charge by controlling the burning rate but there being only 3 (?) burning rates makes it clumsy, the best.

Ok, here we have confirmation that an allomancer burning a feruchemical charged metal will be releasing the f-charge and not the a-charge. But can he use it always? Here it works with the allomancers Identity (remember, he himself charged the metal without storing his Identity away). The reason for this to work could still be the charge recognizing the allomancer as his owner. And no, I was not treating Identity an an enabler for Feruchemy, just as an explanation why the charge goes back to its owner, lacking the ability. I could reply that you are treating an unkeyed f-charge as an enabler to Feruchemy - at least to tapping. Which I think is not possible, and the above example cannot be taken as a confirmation for that theory, since there is the loophole with Identity. In both the gold and steel examples. I don't say it is impossible either (I only think that it doesn't work, not improbable that I am wrong there), just that the example does not fit. The preconditions don't fit to allow any logical conclusions. Both scenarios say that an allomancer burning a metalmind with his identity gets the feruchemical power stored in it (x10 or so). Nothing less and nothing more.

Ah nice, you found some of the WoBs I was looking for and couldn't find. Summarizing: Spikes steal part of the soul. Damage can be healed by patches of Investiture (which is not so different from gaining abilities, where Investiture leaks into holes in the soul). My recollection of the soul staying unharmed in the SR as a blueprint could not be confirmed. If and how you heal (with healing ability) is a matter of how you contemplate yourself to be whole, so it's a cognitive thing. Its not the same as the spiritual Identity, though the concept is similar. Your Identity should stay the same, whatever happes to you (except you're storing Identity in a metal mind - that redirects it), while your Cognitive Self is how you think of yourself, if that makes sense. What we asked was whether an allomancer can use the released feruchemical charge while burning an unkeyed metalmind. The Miles scenario was answered with "Yes, that would still work. It'd still have a Spiritual connection to him." Here a keyed metalmind was used, stored with Miles health. Miles is missing sDNA corresponding to his f-gold, but he is still "Miles" and thinks of himself as this. Also the spiritual Identity of Miles should not have changed just because he lost part of his soul. The ideal is still the same. So the charge being burned recognizes him as the rightful owner and heals him, patching his sDNA back with a new part of soul - because that is the way he sees himself as healthy and his stored health flows there where it belongs (in the scenario Miles was even burning f-gold while being spiked, so the process of releasing health was ongoing and didn't have to be started without feruchemical abilities). It's an interesting scenario in itself, but the more I think about it, the less appliable it is to our original theory. It's an example of quite the opposite we are theorizing about. The point is, a misting without being a twinborn, would not have the feruchemical ability granted by an unkeyed charge. Not anyone can use unkeyed metalminds, but any fering with that metal or a feruchemist (who are really rare in era 2). Thats's the idea of compounding: You fuel feruchemy with allomancy. You need to have the feruchemical power to do this. Identity just keys stored powers to the person having stored it, more or less a protection from theft. You can create unkeyed metalminds on purpose, they can be used by any feruchemist, but they don't grant feruchemical abilities by themselves. To achieve this, you would need to use Southern Medallions or the BoM, granting the ability temporarily. About Vin: You're right, I hadn't that particular scene in mind. This scene still does not imply that Vin would have been able to use the Investiture (I really have to search the books, unfortunately not as ebook...) if it were unkeyed. But, if she burns it as a normal allomantic metal, it shows us that you would at least get the allomantic effect when burning an unkeyed metalmind and not just a puff of hot air. The in-system reason is that Miles metalminds were filled with and keyed to him via his Identity, the charge recognising Miles while it was released. The burning was already on while Miles was being spiked, so the keyed health could flow back to where it belonged. This would not apply to unkeyed metalminds. Unclear is, if the burning being in progress while Miles is spiked (in that hypothetical scenario) is relevant or not. In the Alloy of Law, Miles also allomantically burns gold. Either he has uncharged metal or he is able to select which kind of power he gets from burning gold. Again, have to look up some more about compounding...

1.) Vin is able to sense the charges just from the fact that she can push on the metalminds only with difficulty, since they are filled with Investiture. And anything filled with Investiture is hard to influence. 2.) I don't think that is how spiritual links work at all. In the spiritual realm Miles would still be in his perfect state without damage - compare with healing of shardblade wounds. The healing itself is a cognitive process while the blueprint to be healed from is found in the spirit web in the spiritual realm. IIrc, someone who is killed with Hemalurgy stays only for a very short time in Shadesmar, but his soul in the Spiritual Realm will be whole. (Will edit this post later after some WoB research) Relevant WoBs: Will have to find the explanation on Reddit...later

Actually, if above theory is correct, any misting could become a compounding twinborn with the right medallion. The compounded feruchemical charge can be stored in an unkeyed medallion, which could be disassembled to burn the metal with charge again. It's a bit clumsy but with industrial mass production in mind, that procedure could become easy and common knowledge. The only limitation here is the availability of the metals - which should become much scarcer after a while. Wars for resources come to my mind and are not unheard of - just to speculate a bit more. But still, the mechanism of allomantically burning feruchemically charged unkeyed metals could still just have the same effect as burning normal metal, since the spiritual connection to the charge would be missing. The charge would be there but could not be used since the feruchemical ability is missing. I need to look up some WoBs on compounding, but if i recall correctly, burning a metalmind releases only the f. charge tenfold. So the poor misting burning an unkeyed metalmind wouldn't even sense the f charge since he is no feruchemist AND he would not get any allomantic power. Could be he gets nothing but an angry stomach... Oh one thing to that WoB: It is in regard to a very special hypothetical situation where the f charged metal is burned after the f ability has been spiked out hemalurgically (and the former twinborn still lives) He would be able to burn the gold charged with his own health to heal himself - because the charge has still connection to him. The connection is the reason for this to work. An unkeyed metalmind lacks exactly this connection so it would be useless in that special situation. Spitual connection then would have not been neccessary to explain the possible healing. Edit 2: I would not equate spiritual connection with identity. Even if someone fills an unkeyed metalmind (while storing his identity in another one) there still could be a Connection to that charge. It would just be usable by anyone. Doesn't matter that the WoB is pre BoM, Brandon had his magic ready, probably before the release of The Final Empire.

The WoB above is not quite appliable to the theory in the beginning. The described scenario in the WoB has a filled metalmind with identity(connection) attached to the user who burns it. So Miles would be able to use the stored healing because it is still connected to him. If he were burning a goldmind without his identity (connection to him), it could be that he would be able to use the charge, or not. We just don't know. Actually, there are some hacks to feruchemy, allomancy, hemalurgy and compounding out there, which were probably not intended the way they turned out to be, making the combinations very (too) powerful. I am really curious how Brandon will fix that with some limitations in future books, since all powerful magics are not really his thing (refering to his writing classes at BYU). There still is room for this, since we got a lot of information from more or less unreliable narrators with incomplete knowledge of the magic system and WoBs are not 100% canon either, until they are written in a released book. In this frame of reference, I would bet on the theory above is not working, since it would make the magic too powerful. So I guess, an allomancer burning his metal with an unlocked feruchemical charge will just get the same as an allomancer burning that metal without charge, as long as he doen't own the feruchemical abitily as well. Wearing a medallion might change that though, since all passengers on the skimmer were able to store weight, regardless of allomantic/feruchemical abilities.

I am quite sure he will read in English, otherwise it would be a reading from a translated book. That would be much less interesting than a reading from Oathbringer or perhaps Snapshot. But that could be only me, thirsting for more snippets from Oathbringer.

Brandon was at the Leipzig book fair on Friday, March 24th and Saturday 25th. There were three readings, three Q & A and four signings, which gave us some opportunities for interesting questions, and we got some meaty WoBs. All announced transcriptions are there now. Big thanks to all of you who went to the signing lines and asked those interesting questions, and special thanks to @She Who Cannot Be Named and @mr42 for transcribing! Reading Leipzig Friday, 24.3.2017 - Schille Theater - Signings (transcribed by @She Who Cannot Be Named) Saturday morning: Q+A during the event and signing afterwards (no writing tipps) (transcribed by @She Who Cannot Be Named) Saturday afternoon: (transcribed by @mr42)

Well, that we can only can speculate about, since we don't know what it feels like to have a gemheart. Parshendi should be able to know about their gemhearts without dissecting corpses, what they most definitely don't do, anyway: Parshendi are after all able to see spren leaking from the cognitive realm to the physical realm, so when they trap/invite a spren to their gemheart, they should be able to see/feel where the spren goes to. As long as they are not in slave-form (Parshmen), capturing a spren should be something instinctive to do. After all that's what they are doing since prehistory on Roshar (See the Song of Listeners:) From "betrayed" I conclude that there was a (natural) symbiosis of spren and Parshendi, even before humanity came to Roshar. The closeness of their minds to the cognitive realm giving them their froms plus the information from the Oathbringer prologue makes me think, that Parshendi are aware of where their spren stays after capturing it. "Though broth are we, their meat is men." implies (for me) that the symbiosis of spren and Parshendi is something basic, perhaps just the Parshendi giving the spren a place to stay on the physical realm like it's done in fabrials (though that's more like enslavement of spren), getting their form in return, while we know that the Nahel bond provides sapience for spren (in the physical realm) and access to surges for the human. There is more, if one considers the forms of power, which were shunned by the free Parshendi, and the possibility to bend the surges of men to the surges of Parshendi, but that would go too far here. An explanation for the Parshendi not to touch their dead could be: In early history, Parshendi looted and disected killed enemies (tribal wars, etc.) to get to their gemhearts (compare to historical cannibalism in Polynesia, where enemies were eaten to get the strenght from the killed enemy). This practice being "a bit" messy could have led to a taboo in touching the dead at all, to prevent such atrocities.

Again, I put my arguments spoiler tags for Oathbringer prologue, since I refer to it. An argument came to my mind, to give a loophole: Parshendi might call their uncut gemstones "gemhearts", since that's what the uncut stones are: Gemhearts of cremlings and other smaller animals. But, also in the Oathbringer prologue:

The Oathbringer Prologue gives an answer to the question whether Parshendi have a gemheart or not. I'll put it in spoiler tags, it hasn't been discussed right now, yet:

Actually I only had in mind the possibilty of Gavilar visiting the Nightwatcher on his own, not together with Dalinar. But as I wrote before, that is unlikely because Gavilar is even more orthodox Vorin than Dalinar. I really don't like Gavilar at the moment. Still he is influenced by his visions and probably by something else, easily making him a puppet orchestrated by at least two shards so I am hesitant to judge him, yet. I am prepared for another twist... So, while we all discussed Gavilar and other stuff, I think there is another tidbit of information, we should consider: Here we get another confirmation that fabrials work by capturing/enslaving spren. The analogy to a spren in a gemheart though, is breathtaking: 1.: Parshendi have gemhearts (not only greatshells). 2.: Parshendi apply their forms by capturing a spren (opposed to bonding a spren). Now one can speculate whether greatshells also form their symbiosis with spren via capturing them in their gemhearts or if there is another mechanism. The next question contains minor spoilers from "The Thrill", so I put it in Spoiler tags.

I don't know whether many believe it a real possibility, I for sure do. Hints to this end I see in Adolin talking to his shardblade and perhaps getting some feelings back from it. Since that blade is an Edgedancer blade (if I recall correctly) and I cannot see Adolin fitting to be an Edgedancer, this combination probably won't work to revive the blade, though. This blade is an Edgedancer blade and Maxal's post in following thread (too long to quote here) has persuaded me, that Adolin shows many traits similar to Lift, so he might bond his shardblade and revive it. And spren don't die in a human sense. As Syl said, humans are odd. A broken spren is still a spren. What happens if the "owner" of that broken spren starts to think of it as something alive? As a cognitive entity, the spren might become alive again after it has been thought of as "alive" for a sufficent long time. Talking to something might be a path to that end. I have in mind little children talking to their teddies and imagining them as alive. When I was a kid, I guess about 4 years old, I started cutting the fur of my teddy, because I was sure it grew back - didn't work with the teddy, perhaps I would have had more luck with a spren ;-) My thoughts towards Gavilar: My first reaction was "What a JERK!!! Kill him!", contemplating a bit more, this prologue cries "RED HERRING!!!". No more time to elaborate now, but the general discussion already includes many of my thoughts. Just one item: Gavilar (or the people really pulling the strings) probably had backup plans in case something went wrong (like the highly improbable assassination of the king). Some elaborating now: We got an early version of the prologue of book 3 in a 10 book series. Even if we consider arc one, the first 5 books only, we are just in the middle of that arc. In my opinion this is far to early for Brandon to put all cards onto the table. Gavilars motives don't look good here, combined with Amaram's snippets from WoR, assuming their goals coalign, they stem from religious fervor. The Vorin ultras want their gods back, so they have to be lured out of hiding. But what is behind this? I feel we are missing another layer of sceming - that of Cultivation. We know from Dalinars visions, that Cultivation was much better in seeing the future than Honor was, giving her some powerful means of sceming. Wyndle calls the Nightwatcher his mother. Syl calls the Stormfather her father. In analogy to the Stormfather, the Nightwatcher should be Cultivation's mind (not Cognitive Shadow, since Cultivation still lives, as far as we know). We know that many people go to the Nightwatcher to get their boon and curse, which gives Cultivation a great means to influence things on Roshar. Taravangians Diagram could be her plan from the beginning (not necessarily the resulting consequences). Question is: Was Gavilar also in the Valley, visiting the Nightwatcher? Probably not as an orthodox vorinist. None the less, the Diagram says the desolation needs no usher. I think this is true. The appearance of the desolation depends - in my reasoning - on the breaking of Taln. As soon as Taln breaks and leaves Braize, the Desolation will come. The resulting everstorm, which is a new phenomenon, might be caused by Gavilars scheming - but not the Desolation itself. His ushering might even have positive effects in the end - if the Heralds are lured out of hiding by it and become sane again somehow.

We might be able to get some hints from Mistborn: Secret History, though information about spatial relations might get mingled with a disturbed perception of time. I don't have time for a reread with that aspect in the back of my mind now, just wanted to hint at the possibility. While contemplating spatial relations in the CR one also should keep an eye on temporal stuff. So well used objects should have a representation in the CR well after they don't exist in the PR anymore...

My best guess is that Trell and Nalt are two aspects from one shard, not local to Scadrial. Worshipped is the Night with a thousand stars rivalled by Day with a glaring sun. Not being sure which spoilers are allowed, I hint to the system descriptions in AU by Khriss and a shard that acts hypocritcally.

Considering the nearly total memory loss of Syl and Pattern and the partial memory loss of Wyndle despite preparations, I think spren who are going to bond are pushed from the Cognitive Realm to the Physical Realm and suffer some kind of trauma. A slight manifestation in the PR while staying mostly in the CR sounds more like Shallan watching into Shadesmar (just the other way around) which is the careful approach of transitioning. A quote from WoR (p.704) On the other hand it could be that the Nahel bond makes transitioning between realms easier for spren, so they don't get traumatized each time when they coalesce as shardblade, -spear or -fork in the PR. So partial transitition without Nahel bond = trauma and total transition (temporarily) with Nahel bond = no trauma. The Parshendi affinity to Shadesmar might make the transition from the CR to the PR and the bonding of voidspren really easy. Put into the bowl the assumption that a highstorm is a moving perpendicularity (not necessary but making the mechanism even easier), or something similar, the upcoming of a desolation consists of the jump of voidspren from Braize to Roshar (in the CR) followed by the bonding with Parshendi in a highstorm to transition (partially) to the PR. And to bring the argument back to where it started: For this mechanism to work, the appearance of KR on Roshar has absolutely no significance, so Ishar's and Nalan's argumentations are lies / denials of unwelcome truths.

Ah well, my crappy mobile post wasn't posted at all - no matter. You might use just a recursive representation, like cos(2^(a+1)*x)=2*cos^2(2^a*x) - 1, but that's probably not what you want. For a series you will also need sin^n(b*x) terms. The Moivre formula comes to mind here, if I remember correctly it is derived from: cos(nx)+i sin(nx)= exp(i*nx)=(exp(i*x))^n=(cos(x)+i*sin(x))^n (*) You can expand this binomial using binomial coefficients which i have no idea how to type in this forum, so let me just define bin(n,k):=n!/(k!*(n-k)!) (*)=Sum(k=0...n) i^k*bin(n,k)*cos^(n-k)(x)*sin^k(x) (In this sum k runs from 0 to n) Collecting real and imaginary terms yields formulae for cos(nx) (real) and sin (nx) (imaginary). i^2=-1 leads to alternating signs. So cos(nx)=cos^n(x) - bin(n,2)*cos^(n-2)(x)*sin^2(x) + bin(n,4)*cos^(n-4)(x)*sin^4(x) - + - +... set n=2^a and you've got a series for your problem. But I am really not sure whether that is as handy as desired... If you are uncomfortable with the sin(x) terms you can still use sin^2(x)+cos^2(x)=1 and replace the sin(x) terms (which all have an even exponent, so no roots involved). Best ingredients for a pen and paper evening ;-)

Obviously, as Stick has stated clearly - and repeatedly - Stick is a stick. Stick is not awakened, so it is neither class, but, as an object, Stick could be awakened as a Class III or IV entity. Stick's strong cognitive personality makes a demanding and convincing application to be awakened as a Class IV entity. As for Nightblood: I guess the biggest threat comes from Nightblood consuming Investiture exponentially with his drawing-duration. I am not quite sure, but I think I read somewhere that Investiture consumed by Nightblood is corrupted and does not return to the system. So Nightblood could be a means to destroy or corrupt a Shard's Investiture completely, if one could lure a Vessel to draw him long enough.

For the sake of simplicity it would be easiest to identify darkside magic with Skycolors. The thing that doesn't fit for me though is that Scythe's powers have some mysterious touch with many rumors running - which are confirmed by Baon - while Skycolors seem to be something ordinary on darkside so that Kenton having no Skycolors is strange enough for Khriss to mention it at all. Of course this could be just due to the fact that the prose version we read is not polished and that "discrepancy" would have been mended in a release version of the book. I am really looking forward for sequels, both because of magic system/worldbuilding and the character development/story. I am not sure whether we will see Khriss become a worldhopper onscreen though, since that part of the story is missing for every other worldhopper for the time being.

But it would drain double the amount of stormlight. And it would require a lot of trust on Szeth's side.