The Kali pattern generator is a part of the Geometry Center at the Science U web site. (See separate review of Geometry Center.) It can also be found at http://www.geom.umn.edu/java . It provides an interactive exploration of the seventeen wallpaper tiling patterns as well as seven frieze groups and twelve rosette groups.
Please also see the related reviews of the main Science U-Geometry Center site, and another of its subsites, QuasiTiler 3.0