Fire 火 tamed to a point: the traditional 燈 used 登 'to ascend' as sound — flame climbing a wick. Simplified 灯 swapped in 丁 for economy. From oil lamps to LEDs, the character kept its little fire.
元宵节 the Lantern Festival closes Spring Festival with 灯会 lantern fairs and 猜灯谜 riddle-guessing hung from lanterns — a thousand-year-old quiz show. 红绿灯 traffic lights rule modern streets; 开夜车 studying under lamplight rules exam season.
Fire 火 pinned like a nail 丁 to the wall — a LAMP.
灯红酒绿 'lamps red, wine green' paints nightlife in four characters — neon before neon existed.