DMX + MAX485
Arduino TX + RX pin
Universal Asynchronous Receiver/Transmitter (UART): Asynchronous serial communication is managed by a Universal Asynchronous Receiver/Transmitter, or UART, inside the processor. The UART pins are usually attached to internal hardware interrupts that can interrupt the program flow when new serial data arrives, so you never miss a byte. It’s possible to manage serial communication in software alone, but at high speeds, you’ll see more errors.
https://itp.nyu.edu/physcomp/resources/microcontroller-pin-functions/
Possibly to print the optical illusional picture to attract people to step on the sensor we hide underneath.
https://fineartamerica.com/featured/1-optical-illusion-3d-pattern-jodoto-design.html?product=art-print