There is ‘room’ in the matrix for additional keys, and various people have experimented with adding switches. See http://geekhack.org/index.php?topic=26579.0 ht

There is ‘room’ in the matrix for additional keys, and various people have experimented with adding switches. See http://geekhack.org/index.php?topic=26579.0 http://geekhack.org/index.php?topic=26579.0