# Keep only zeroes on the tape

('0', 0) = ('0', 0, >)
('1', 0) = ('1', 0, >)
('Z', 0) = ('Z', 1, <)
('0', 1) = ('0', 1, <)
('1', 1) = ('0', 2, >)
('0', 2) = ('0', 2, >)
('Z', 2) = ('Z', 3, <)
('0', 3) = ('Z', 1, <)
