In the applet below we reconstruct the underlaying girih pattern. [br]The zigzagging lines define 2 types of polygons that appear frequently in the decoration:[br][list][*]Click on the checkbox [b][i]pentagons[/i][/b] to color the regular pentagons in the tiling. [br][/*][*]Click on the checkbox [b][i]octagons[/i][/b] to color the pentagons in the tiling.[br]Click on the checkbox [b][i]model octagon[/i][/b]. You'll notice that the octagon is formed by two regular pentagons partly drawn upon each other.[/*][*]Define the midpoints of all pentagons and [b][i]connect the midpoints[/i][/b] of all tangent polygons.[/*][*]Click on the checkbox [b][i]girih tiles[/i][/b]. [br]You can see that the connecting segments coincide with the girih pattern.[/*][/list]