Great software for Tilings, Patterns, Symmetry
A list of interactive, visual, easy-to-use software or tilings and patterns.
A tutorial on everything about hexagonal grids. Coordinate system, finding path, etc.
Kali (wallpaper symmetry)
http://www.geometrygames.org/Kali/index.html Windows Mac OS Classic
Kali by Jeff Weeks. It is a interactive program for drawing figures of plane symmetry.
[Computer Graphics and Geometric Ornamental Design By Craig S Kaplan. At https://cs.uwaterloo.ca/~csk/other/phd/]