title: Scheme - SubSets of a list
body: <p>I need to write a function that will produce all of the subsets of a given list. I have a recursive version that uses map but for a bonus I am asked to create a function that does it without using explicit recursion, a local, or any abstract list functions. I am allowed to use <code>cons</code>, <code>empty?</code>, <code>empty</code>, <code>first</code>, <code>rest</code> and <code>cond</code>. I am on the verge of a meltdown - any suggestions? Should I be using a lambda statement for each recursion in need to perform? </p>