4 digit charlieplexed segment display

https://www.electronics-lab.com/4-digit-charlieplexed-segment-display/

bobricius @ hackaday.io has designed an ultra thin custom display, requiring only 6 gpio pins to drive 30 leds. FEATURES: – 1.05×0.48 inches (26.67×12.22 mm) – 30 led – any color – ultra thin …. etc. on 0.8mm board – only 6 gpio – ideal for wrist watch 4 digit charlieplexed segment display – [Link]