“Wouldn’t it be really cool to have a mind-controlled flamethrower?” ponders Matt Oehrlein. He’s perched on a solid wooden desk, dressed in a T-shirt and shorts, his sneakers crossed at the ankle and swinging in the air. He’s thin and tall, sporting thick-rimmed black glasses and a shock of bushy brown hair. Around him rises what to an outsider looks like functional chaos: a warehouse-like, fluorescent-lit workshop where a traffic light hangs from the ceiling, a forklift idles nearby, and the shrill grind of a table saw cuts through the air.

Naturally, he already does have a mind-controlled flamethrower. It’s a precarious-looking wooden frame about 3 feet tall, topped by a pair of propane tanks. After some required assembly, Oehrlein dons a Bluetooth-enabled headset, steps on a safety switch, and begins to concentrate. Soon enough, satisfyingly whooshing balls of flame illuminate the street.