In 1997 a Pokémon episode aired in Japan with a four-second red-and-blue strobe. 685 children went to hospital that night. The regulations that followed — Ofcom Broadcasting Code 2.12, ITU-R BT.1702 — are why UK and Japanese broadcast deliveries have to clear a photosensitive-epilepsy check before transmission. I built a screening tool for that check. Live at flashframe-production.up.railway.app , code at github.com/edycutjong/flashframe . Three synthetic test clips ship with it, so you can...