Tail Recursive Reverse Execution
>(trrev '(a b c d))
1> (TRREVB (A B C D) NIL)
2> (TRREVB (B C D) (A))
3> (TRREVB (C D) (B A))
4> (TRREVB (D) (C B A))
5> (TRREVB NIL (D C B A))
<5 (TRREVB (D C B A))
<4 (TRREVB (D C B A))
<3 (TRREVB (D C B A))
<2 (TRREVB (D C B A))
<1 (TRREVB (D C B A))
(D C B A)