The source code is in the larsi-org/LED_Editor GitHub repository.

Building a back board.

Count Part Description
2 Addressable LED strip WS2812B 5M, 30 LEDs/m
1 Wooden board ¾" × 24" × 36" edge-glued unfinished spruce pine fir board

Here is the Arduino source code (check out the larsi-org/LED_Editor GitHub repository):





I wrote a pretty minimalistic editor in Processing. Check out the larsi-org/LED_Editor GitHub repository.