A note on notation:<p>The standard notation for a cons cell with car &quot;x&quot; and cdr &quot;y&quot; is (x . y), not (x y). The latter is a list, equivalent of (x . (y . nil)).<p>So (1 2 3) is equivalent to (1 . (2 . (3 . nil)), <i>not</i> (1 (2 (3 nil))). The latter is a nested <i>list</i>, which is equivalent to (1 . ((2 . ((3 . (nil . nil)) . nil)) . nil))