The first episode of the Mojoptix podcast and video series demonstrates how to create a 3D-printed sundial that can display the time in digital format without electronics. The sundial works by allowing light to pass through a carefully arranged array of “tiny tunnels” that turn the individual pixels of the display off and on as the Sun moves through the sky.
For anyone interested but unable to 3D-print the parts themselves, kits are available for purchase that come with all the parts needed to assemble the device.
via Make: