4 designs for analog clocks that reset when a player sleeps in a bed. One uses pistons displacing lava as its display, one uses powder snow over grey maps. I have also included a regular piston and a lamp design as examples. The mechanisms behind all of these are my designs, though the latter two displays use existing ideas.
Feel free to use in your Minecraft worlds.
Companion youtube video: www.youtube.com/watch?v=IY9thwS24lE