To play backgammon, type the numbers of the points from which pieces are
to be moved. Thus, if the roll is '3,5', typing '2 6' will move a piece
from point 2 three spaces to point 5, and a piece from point 6 forward to
point 11.  If the moves must be made in the opposite order, the first
character typed must be a minus ('-'). Thus, typing '-2 6' moves the
piece on point 2 by 5, and the piece on point 6 by 3.

If you want to move a single piece several times, the sequence of points
from which it is to be moved must be typed. Thus '14 17' will move a
piece from point 14 to point 17 and thence to to point 22.

If a double is rolled, you should type four numbers.  Red pieces that
have been removed from the board by being hit by white are on point 0 and
must be brought in before any other move can be made.  White pieces that
are hit are removed to point 25.  You will not be allowed to make an
illegal move, or to make too many moves. However, if you make too few
moves, the program does not care. In particular you may skip your turn by
typing a 'new-line' all by itself.