Hesitatingly, I'll dare ask a question of rather specific nature: The generating function of planar partitions is 1 / prod(n>=1, (1 - q^n)^n ) Now that is also the g.f. of (the usual) partitions with one sort of 1, two sorts of 2, three of 3, etc. I am the only person on this planet that cannot figure out a (natural, constructive) bijection? Best, jj