TODO

   1 Hmm... non ? -->
   2 Otage, Emergo, Pacosako : fonction "buildPiece(arg1, arg2)" returns HTML element with 2 SVG or SVG + number
   3 ==> plus simple : deux classes, images superposées.
   4
   5 https://fr.wikipedia.org/wiki/Unlur
   6 Yoxii ?
   7
   8 Idée new variant: "bed" random moves and "capture" (opponent?) pieces which cannot move on next turn (sleeping). (Crazybed ?)
   9 one "bed" per player.
  10 one turn = place bed (potentially with opponent piece), then normal move, then random bed move - dropping potential piece on initial square (awaken).