Infinity Mirror Clock
A strip of Neopixel LEDs inside a brushed metal case, sandwiched between mirrors gives that "infinity mirror" effect to this clock. Hours are in blue, minutes are in yellow and seconds are in red; hence it's about 2:50 in the video below. Easter eggs hidden at 3:04 and 7:11, like most of my clocks.
How its done: Arduino Nano, DS3231 RTC, 97 Neopixel LEDs on a strip. The casing comes, ironically enough, from an old battery-powered Westclox wall clock with the guts removed. Based on the Neopixel Ring Clock, conceived by Andy Doro.