Zelly

Google "how to draw radial symmetry".
Start with a light circle and draw bisecting lines through it like a pizza. Each "slice" will repeat, so just be careful that the lines you make in each section are the same length and direction each time.  You could also make the pattern you wanted on a separate slice and then trace it for each section to ensure that each is identical.
If you want to mess around with radial symmetry online, there's places like this: https://www.myoats.com/create.aspx

I think this is the simplest explanation of the two.  Physical/organic is done directly by a person, mechanical with an external device.  It's flying by one's own power vs flying via rocket boots.
Hmmm Hemalurgy and souforging are weird.  They're both technically external, but then become the person.....I guess they're both.  When invested but not in use they're mechanical, when used on a person they become physical as it's the person using them?