Some tessellations you can open out and close up.
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
 D. Wells, The Penguin Dictionary of Curious and Interesting Geometry, New York: Penguin, 1991.
Wolfram Demonstrations Project
Published: January 3 2013