Pentominos

The Pentominos 10x6 placement is the 1st serious problem I coded. I was probably 12 when I designed my first backtrack with Connected-component labeling in -oh god- Basic on MO5. I was probably 14 when I coded it in GFA Basic on Atari ST and later rewrote it in Assembly - It took then less than a week to find all solutions !

A generic solver

I’ve published a generic solver on github, in Haskell :

The full solution set,

As computed by the haskell solver above, the 2339 solutions :