“I know exactly how she’s setting them off.  Toe rings.”

“Toe rings,” Grue said, disbelief clear in his tone, even with his warped voice.

“She’s got a ring around her big toe and the toe next to it.  When she crosses one toe over the other, contacts on the outside of the rings meet and it sends the signal.  She chooses the target with a system built into her goggles.  It doesn’t look like she’s doing anything, which is probably the effect she’s going for.  Appearances.”

Wildbow, Worm, 4.9