This vintage combo achieves an infinite turn loop by recycling a single copy of Time Walk through the graveyard every single cycle. The engine is fueled by Kykar, Zephyr Awakener, whose triggered ability exiles Skullwinder whenever you cast a noncreature spell, setting up its eventual return during the end step. When Skullwinder finally re-enters the battlefield, its triggered ability reaches into the graveyard to pull Time Walk right back into your hand, ready to be cast again on your next extra turn.