I often find myself doing this:
for x in range(x_size): for y in range(y_size): for z in range(z_size): pass # do something here
You can use itertools.product:
>>> for x,y,z in itertools.product(range(2), range(2), range(3)): ... print x,y,z ... 0 0 0 0 0 1 0 0 2 0 1 0 0 1 1 0 1 2 1 0 0 1 0 1 1 0 2 1 1 0 1 1 1 1 1 2