There’s quite a bit of POV (Persistence of vision) projects lately. Most POV projects are a series of LEDs (lights) blinking and when moved produce a word- it’s the same “hack” when you play 30 frames a second to see a movie. A couple years ago I made a pair of shoes that spelled “NIKE” when you run (View image) and when I get time, they’ll display speed too. If you’re interested in the POV “movement” here are a few great examples to get started. Drewish’s 2-sided pov toy, Lady Ada’s minipov and Make pal EverythingDigital’s recent posts using off the shelf parts.