Bicycle Directional LightsFantastic Auto Lights
Following the theme of charlieplexing, searching the network I found a circuit of a led matrix, in which text can be moved, the matrix is ​​4x5 and only uses 5 pins, ideal for use with the digispark plate as in the previous topics .

The materials for this project are:

1 protoboard
1 digispark (you can also use any arduino)
5 resistances of 100 ohms
20 ultra bright leds
several connection cables”

Link