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Squares is a one-sided surface, like a Möbius strip (or to be exact, like several Möbius strips joined together along the edges of a tetrahedron).  Here I've peeled that surface apart, separating its sides...but since it had only one side, I still have only one surface.

This piece has 24 spheres of tungsten carbide, a very tough, dense, corrosion-resistant material, held in tension settings.

Double Squares metal print, 3 1/2" diameter - $410