Details

Open the tessellation, extend its region, zoom in or out, drag to pan the image, or select a different tessellation.

Such tessellations are composed of solid pieces hinged at their vertices and separated by empty space. At some intermediate positions, the white spaces assume regular shapes.

Snapshot 1: tessellation of equilateral triangles of two sizes

Snapshot 2: tessellation of squares and rhombuses

Snapshot 3: tessellation of crosses and 12-gons

Reference

[1] D. Wells, The Penguin Dictionary of Curious and Interesting Geometry, New York: Penguin, 1991.