Related: 24 Creative Jack-O-Lantern Ideas to Up Your Pumpkin Carving Game One of ... will-o’-the-wisp—an unsettling and inexplicable light emanating from a darkened forest or dense swamp.

[Paul] first wired up an RGB LED to a Raspberry Pi ... so it easily diffuses the light. The result is a jack-o-lantern that glows different colors as defined by his party guests.