Any small portion of the code in any of these directories can be used for any purpose at all, and in any commercial or free software. However, Ergo itself (in its entirety, or in any substantial portion) or any directly derivative works from a substantial portion of Ergo's code should be considered to fall under the standard, general GNU license, which disallows selling Ergo itself or any derivative works and which places responsibilities on the users of Ergo's code to provide sources to anyone who asks. My intention is to allow anyone who wants to use Ergo for personal use to do so, and to even allow some borrowing from Ergo, yet I always want Ergo to remain free to everyone. Charles