Islamic Art Tool
This sketch has an Islamic Star, a recurring design in fantastic Islamic art tessellations. But it also has a tool, so you can make multiple stars and design a tessellation yourself. If the user tool isn't working in the browser, try downloading from the teacher page:
http://www.geogebratube.org/material/show/id/51256
To explore a single star more deeply, try this sketch:
http://www.geogebratube.org/material/show/id/51257
Riff off of a Jennifer Silverman sketch:
http://www.geogebratube.org/material/show/id/51190