exact-covers
creating exact cover matrices for polyomino problems, as described by Knuth in his article "Dancing Links".
a rectangular region is just two numbers, (n m), n is x width, m is y width
a polyomino is a list such as (2 3 (0 1) (1 1) (0 1))
we get all possible configurations with paddding.
the result will be a list of lines. e.g., for a region of (4 5) and the polyomino above, we start with ((0 1 0 0 1 1 0 0 0 1 0 0 0 0 0 0) (0 0 1 0 0 1 1 0 0 0 1 0 0 0 0 0) (0 0 0 1 0 0 1 1 0 0 0 1 0 0 0 0) (0 0 0 0 0 1 0 0 1 1 0 0 0 1 0 0) etc. ) the spaces in the list is just for readability of course (and I am not sure they will show up in markdown).
I'll try to use this as an oppurtunity to use classes in Common Lisp.