What geek doesn't love blinky lights? Here is a fun little hack in Rust on the MicroBit nRF52 based board that demonstrates the classic "Persistence of Vision" effect. Here we use the MicroBit's accelerometer and LED array to display the message "Hello" as the board is rotated. The code is derived from the excellent Rust Embedded Discovery Book examples. It works best if you fix the board to a stick, I used a ruler. As you sweep the board in arc the magic appears as shown in the picture above.
Here is my setup:
Here is just the blinky lights up close: