No, I'm saying that the Pits are the perpendicularity. That, based on the evidence we see in Mistborn, the liquid that would have formed a shardpool like the Well of Ascension is instead condensing into atium geodes.
I am well aware that there is only one per Shard, and I am of the opinion that it does not necessarily have to be in the form of a pool. It's wherever that Investiture gets concentrated—which, in the case of Ruin, is the Pits, in the atium.
I tried looking for some WoBs, just to see if he's ever said anything about Ruin having a pool, but I can't find anything on that. Until we get that WoB, this is my theory.