A clock that shows the progression of time through the daylight hours - on a grid.
The yellow (or orange or red) spot is the current time, and moves to the right and down through the day. Each spot in the grid marks five minutes. Each row is an hour. Daylight is shown as blue, dawn and dusk are fainter, and dark indicates night - its position shows whether it is AM or PM. (Come along to watch it flip at midday or midnight!)
I exhibited the clock as an installation at EMF 2026.
Here is a photo of it next to some other clocks later at night (notice that the spot is red since it's after dark):
I first implemented and wrote about a block clock in 2002.