#|
 | Copyright (C) 2017 Ortega Froysa, Nicolás <deathsbreed@themusicinnoise.net> All rights reserved.
 | Author: Ortega Froysa, Nicolás <deathsbreed@themusicinnoise.net>
 |
 | This software is provided 'as-is', without any express or implied
 | warranty. In no event will the authors be held liable for any damages
 | arising from the use of this software.
 |
 | Permission is granted to anyone to use this software for any purpose,
 | including commercial applications, and to alter it and redistribute it
 | freely, subject to the following restrictions:
 |
 | 1. The origin of this software must not be misrepresented; you must not
 |    claim that you wrote the original software. If you use this software
 |    in a product, an acknowledgment in the product documentation would be
 |    appreciated but is not required.
 |
 | 2. Altered source versions must be plainly marked as such, and must not be
 |    misrepresented as being the original software.
 |
 | 3. This notice may not be removed or altered from any source
 |    distribution.
 |#

(print "Use Ctrl+C to exit.")

(let ((n 1))
  (loop
  	(defvar a)
	(format t "~%2^~a=" n)
	(setq a (read))
	(if (= a (expt 2 n))
	  (progn
		(print "Correct!")
		(incf n))
	  (if (= a 0)
		(progn
		  (print "Goodbye!")
		  (return nil))
		(print "Wrong answer, try again.")))))