We were working on Islamic tessellations in class, and Ashley Short came up with a nice one, that had several different structures.[br][url]http://ashleynshort.weebly.com/mth-495-spring-2014/tessellations#comments[/url][br][br]That was enough to get me experimenting with intentionally leaving a gap. [br]So my first try has rotation points fixed at a third of the distance along the triangle ([url]http://www.geogebratube.org/material/show/id/118949[/url]), and this one allows you to set the rotation point. So this could be a simple midpoint rotation tessellation of an equilateral triangle, or you can get funky.

More GeoGebra at [url]mathhombre.blogspot.com/p/geogebra.html[/url]