Mike Marcum didn’t have a lab, funding, or a PhD. Just a pile of salvaged electronics — and a theory. One night in Missouri, he fired up his homemade device. It formed a vortex. He tossed in a screw.

Experiential artist Lucas Rizzotto was going through a tough breakup, so he did what anyone would do: he built a personal time machine. In a playful talk, he shares how his free-ranging ...