mathgrant’s hybrid type: a Fillomino (write a number in every empty cell so that every group of cells with the same number that is connected through its edges has that number of cells) where each tetromino has had their 4s replaced by one of L, I, T, or S describing their shape, and they obey the rules of LITS — they can touch if they are not congruent, they must all be connected, and their squares cannot form a 2x2 block.
This is from the “constructed and procrastinated forever before posting” pile.
My current code base still works, but I’m beginning to realize how horrible it is — it’s not just the mock-function-objects. Time to learn Scala and rewrite from scratch!