def steps_to_repeat_per_axis(universe):
initial_universe = copy(universe)
steps_to_repeat = []
for axis in ['x', 'y', 'z']:
moons = [parse_moon(str) for str in inputs]
universe = Universe(moons)
universe.step()
while not universe.equal_on_axis(axis, initial_universe):
universe.step()
steps_to_repeat.append(universe.steps)
return steps_to_repeat
