Try wrapping your head around this one. An Etsy seller in France has somehow managed to design a remarkable 3D-printed sundial that shows the time as digital numbers that actually change as the day progresses and the sun moves across the sky.
Mojoptix's Digital Sundial does have its limitations, though. The complex pattern of holes in the wand that create the shadows needed to display numbers can only show the time from about 10am in the morning until about 4pm in the afternoon. The digital numbers also only update in 20-minute increments, but that doesn't make this creation any less incredible.
If you're curious about how the sundial was engineered, its creator has posted a 15-minute video explaining the design and maths behind it which you can watch here:
But if you just want to buy one, you can head on over to Mojoptix's Etsy store where you'll need to specify your colour preference and whether you live in the northern or southern hemispheres to ensure it displays the correct time for you.