Make a level with two lemmings, both of which must be saved, and both of which must take different paths to get to the exit.
You are only allowed one entrance and one exit.
You must not have exactly one climber. None is fine, two or more is fine. The same applies to floaters.
Both lemmings must use at least 4 skills each. (As usual, without skill wasting)
It must not be possible to send them both via the same route. However, it's acceptable (but not required) to make it so that either lemming can go either way as long as they both go different ways. It's also acceptable (but again, not required) to have more than two possible routes, as long as the two lemmings must each take a different one.
Any release rate and time limit is fine. Any skillset is also fine, as long as it follows the rule above about climbers and floaters.
EDIT: As usual, glitch solutions do not count either way.