Can be stacked for several bit adding (except for one of them i believe), one is 32 bit. (made without worldedit) They have overflow (except for the one that i believe can not stack). Has carry in feature, and uses logic gates EG: XOR
Pull (labeled) lever/s down and watch the (labeled) lanterns light up with the correct answer (you must add the lit lanterns for answer)
to turn off a number pull lever up, one of them has no overflow so can only display 1 (for the current moment), I do not recommend adding the sums with the 32 bit one, it can be deadly for your brain.