These variants introduce a new piece type besides pawn and king, or new
cell/move types. There are no plans to support them, but who knows...

Big Shot Checkers
-----------------

Played on 8x8 board. There is one Big Shot piece replacing one pawn at
the start. The game is played by normal checkers rules (usually English
rules), so it ends when no moves or no pieces are left for one side.

Additionally, Big Shot piece can move like a king. It can be swapped with
any own piece next to it as a new kind of move. The game is also won when
a Big Shot piece becomes a king.

Tower Checkers
--------------

Played on 7x7, 8x8 or other boards. The pieces are captured by stacking
below the attacking piece rather than annihilating. The attacking piece
becomes a tower. Towers can be up to the total number of pieces tall,
and can be of a single color or of 2 stacks, each of one color.

The captured opponent pieces, if any, are always strictly at the tower's
bottom. The top tower piece determines the tower ownership. Only the top
tower piece is captured and is placed under the attacking tower, so a
tower can change ownership after being captured.

Armenian/Turkish Checkers
-------------------------

All 64 cells of the board are used (both dark and light). The 16 pieces
for each opponent are initially placed on the second and third rows.

The pieces can move forward/left/right (and forward-left/forward-right in
Armenian), and can capture forward/left/right (and backward in Armenian).
The kings add backward directions and can fly.

