Idea 1: The Creeping Shadow Clock

Not long after we moved into our current house I noticed that on sunny afternoons the streetlight across the road casts a shadow on the house opposite:

And as the afternoon goes on the shadow slowly inches across the house, which I captured in this note in my sketchbook in 2007.

This morning I was thinking about how great it would be if I could turn this idea into a clock which would show the time between about 1pm and 5pm by moving the silhouette of a streetlamp across the front of a house.