Arduino Tilt-Controlled Digital Sand (MPU-6050 + 8x8 NeoPixel Matrix)

LED sand that flows whichever way you tilt the circuit! The **MPU-6050** accelerometer measures the tilt, and 24 grains on the **8x8 NeoPixel matrix** fall toward gravity and pile up at the edges like real sand. A **theme button** switches between sand, water, lava and rainbow colors. Library-free I2C reading, turning tilt into a gravity direction and a simple falling-sand algorithm in one project.