They have them now, and I even remember the retarded teevee commercials for them. Eg,
https://www.nighttechgear.com/products/night-runner-270
where I can just imagine the 2 hotspots swinging up’n’down, up’n’down, up’n’down, with every step you take while walking or especially running. Enough to give anyone epilepsy…
Still, Al Bundy deserves all the credit for his invention!