Tessellation WEB SIGHTS:

Escher Websights:

OFFICIAL M.C. ESCHER WEBSIGHT:   http://www.mcescher.com/

MC ESCHER:  http://www.etropolis.com/escher/

Jim McNeill Websights:

OFFICIAL JIM MCNEIL WEBSIGHT:   http://www.jimmcneill.com/

JIM MCNEILL INTERVIEW: http://www.thefreelibrary.com/Tessellation+Artist+Jim+McNeill-a058492256

Islamic Tile Websights:

Investigating tessellation patterns:  http://www.hellam.net/twinsite/