[vshtfncp] Abstract chess piece symbols

Chess requires 6 different piece types, or 2*3.  We consider representing each piece type by a 2 dimensional abstract symbol.

The outer shape can be a square or a circle.  An inner symbol inscribed within the outer shape can be a circle, cross, or absent.

There remains the issue of depicting the 6 types both in black and in white.

Previously, flippable chess symbols.