This is a custom watchface for the Pebble smart watch. Download it.
It looks like this:
It's darker version of the illusion watchface by dmnd, originally by Tokyo Flash. I find it's a better fit for my black pebble.
Although it may not be immediately apparent, there are 4 large numbers on this face. It works by having a background of lines going one direction, while another layer has lines in the other direction. The number digits change the direction of the lines.
Thanks to dmnd for the code. I just touched a file. =]