This is a minimal permissive license found in softSurfer. Originally, it was missing permission to distribute, but that was corrected by upstream in 2013. It is Free and GPL-compatible.
// Copyright 2001 softSurfer, 2012-13 Dan Sunday // This code may be freely used, distributed and modified for any // purpose providing that this copyright notice is included with it. // SoftSurfer makes no warranty for this code, and cannot be held // liable for any real or imagined damage resulting from its use. // Users of this code must verify correctness for their application.