So i just finished a spacechem level that has taken me at least 6 months; as in, i got stuck on it, and have up. Occasionally I came back to it, only to be frustrated from being out of the loops.
Then I was in the bath tonigt, and the answer finally broke in my head.
The problem was a level where you're given h2o, and have to output h2, o2, and plutonium. The problem is, plutonium has an atomic weight of 94, and oxygen has an atomic weight of 8. 8 doesn't go into 94, which only has two factors both prime: 2 and 47. I couldn't figure out how to take these two atoms, h and o, into a one huge nucleus (the level also has a fairly tight limit on the number of factories you can build to transform your matter).
So there in the bath it occurred to me, I would just have to glue 94 hydrogen atoms together. Except that would take too much space. So, glue two h together to give an he, and stick 47 of them together, which you can just about get away with in the space of one factory.
It occurs to me that if weren't a maths teacher, with a good knowledge of prime factors, would this have been easier or harder?
The educational potential of this game is immense.