I was honestly speechless after seeing this solve run to completion. I spent about 8 hours trying to squeeze any optimisation out of my 12I solve that at first I thought was almost impossible to improve. The breakthroughs were having arm 2 drop a reagent after its first grab (to allow room for arm 1 to continue rotating), and getting the exact ordering of the reagent drops on arm 3 right. Arm 3's timing where it drops the required reagents before grabbing the other half of the snowflake is just so perfect and so enjoyable to watch.