Confirm Glide Reflective Symmetry --- Totally Tessellated @ http://library.advanced.org/16661/
Instructions: Print two copies of page (preferably on lightweight or tracing paper) and then close this window. Line up the two pages. Then, keeping the bottom page steady, fold the top page along the dotted line shown below. Take the folded page and move it in the direction and magnitude of the straight arrow. The bottom page should be now uncovered, and the overall pattern (including the top page which should be showing through slightly) is a continuation of the tessellation. Thus, the tessellation has glide reflective symmetry.
