other stuff to do
  1. Auto-solve only works for wedges <= 8 _or_ 1 band, so solves for
    Saturn Puzzle, Hockey Puck Puzzle, and Masterball.  It would be nice
    to solve for all wedges and bands.
  2. GL work
    a. show a gap in pieces (tried a black edge but not right when rotated,
     see WEDGE_EDGE).
    b. add a select from GL to capture wedge and band.  Currently you
      can only move the puzzle from the 2D view.
    c. orient numbers needed
  3. PS_ENDCAP_FLAT (used to draw sectors) does not work in wine-5.0.
    (Oddly, it seems to work when returning from GL display).
