Patience Sorting

Basically, the computer plays Solitaire.

Shift a "card" from front of list and place on top of a stack.

You can only put a card on top of a higher number or on a new stack.

When placing a card on a stack set a pointer to the presently topmost card on the stack to the left.

The first stack ignores this rule; it always points to nil.

• jcoglan blog