Flood fill

Wire an SSD1306 128×64 OLED (I²C address 0x3C) to SDA/SCL, powered from 3.3 V, and light every one of its 8192 pixels.

Tip: adafruit_ssd1306.SSD1306_I2C(128, 64, board.I2C()), then fill(1) — and remember nothing appears until show().