title: (Scheme) Recursive function to compute all possible combinations of some lists?
body: <p>What is an example of a recursive function to compute all possible combinations of lists?  For example, <code>(combine (list 1 2 3) (list 1 2))</code> should return <code>'((1 1) (1 2) (2 1) (2 2) (3 1) (3 2))</code>.</p>