Floor-to-ceiling windows framing wooded hills give this 1974 double A-frame a treehouse feel. The open-plan five-bedroom home has heated concrete floors, wood-clad ceilings, a lofted sitting room ...

360° divided by 20 frames comes out to 18° per frame. So a motor spins the disk around, and every 18°, the light pulses for one millisecond and then turns off until the next frame is in position.