tips if ur on pc (mobile powder toy is worst powder toy. It has less feature): tab to change shapes, ctrl/shift + scroll: change dimentions of said shape. Ctrl+hold/click: BOX shift+click/hold: LINE Ctrl c and v are obvious. Arrows while ctrl v allow you to move pasted item unit by unit. Helps with making straight lines.
would usualy call it bad, but this gave me massive nostalgia for when I was interested in reactors. Reminds me of the save i made where user would have to shove in neutrons to generate heat and then it would melt down. +1 for the feelies