Technical correction: not (let (x y) (f 12) ...) but (multiple-value-bind (x y) (f 12) ...) (There are also multiple-value-call and multiple-value-list,

Technical correction: not (let (x y) (f 12) ...) but (multiple-value-bind (x y) (f 12) ...) (There are also multiple-value-call and multiple-value-list, which are more powerful than multiple-value-bind because they let you get all the values returned without knowing in advance how many there are, but usually less convenient.)