The 12×8 matrix displays your Unlock Symbol (icon or short animation). The board is the UNO R4 WiFi, which has a built-in matrix—use it! docs.arduino.cc
You may use only the pages listed below (Arduino documentation)
Use a LED Matrix Example already included in the IDE, or the LED Matrix Editor to export a ready-to-use icon (no coding from scratch). docs.arduino.cc
Board setup: if you don’t see the matrix examples, check that UNO R4 Boards is installed and the board is selected (IDE 2.x). docs.arduino.cc
How to use the matrix: guidance page with core concepts and basic APIs. docs.arduino.cc
Draw without programming: official LED Matrix Editor to create icons/animations and export ready-made code. ledmatrix-editor.arduino.cc
Getting Started — UNO R4 WiFi
https://docs.arduino.cc/tutorials/uno-r4-wifi/r4-wifi-getting-started
Using the UNO R4 WiFi LED Matrix
https://docs.arduino.cc/tutorials/uno-r4-wifi/led-matrix
LED Matrix Editor (tool ufficiale)
https://ledmatrix-editor.arduino.cc/
Scheda tecnica — UNO R4 WiFi
https://docs.arduino.cc/hardware/uno-r4-wifi
Show the Unlock Symbol lit on the matrix. The teacher notes your time and awards the “Pixel Unlocked” badge.