Simple solid colors, gradients and test line patterns, could be used to test matrices for proper operation, flickering and estimate fillrate timings.

It is also used in CI test builds to check different build flags scenarios.

Should be build and uploaded as a platformio project

To build with Arduino's framework use

pio run -t upload

To build using ESP32 IDF with arduino's component use

pio run -t upload -e idfarduino