[username223]

Scheme, actually, since it uses "define" instead of "defun." I formatted it reasonably, but it still looked like a pain to untangle.

[kazinator]

The original Lisp also used DEFINE. See the LISP 1 Programmer's Manual, Mac Carthy et al. 1960, P. 23.

[gnulinux]

Scheme is a lisp.