Jean Constant - Symmetry
Symmetry is the exact reflection of a form on opposite sides of a dividing line or plane ( Wolfram) It is the result of applying a rigid motion to an object such that it looks the same.
The following is two examples from a 12 plates gallery on wallpaper and tiling symmetries available at hermay.org
Symmetry in physics
In physics the symmetry concept extends beyond what is geometrically visible. Continuous symmetries preserve transformations.
1 = (a)(b)(c)(d)(e)
r = (abcde)
m = (a)(be)(cd)
In homage to Dr Eugene Starostin and Dr Gert van der Heijden who solved the endless ribbon mystery. The symmetry is represented by a diagram that look like the connected sum of the symbols and their mirror image.