// Define the row pins (anodes)
const int rowPins[4] = {2, 3, 4, 5};  // Rows connected to digital pins 2, 3, 4, 5

void setup() {
    // Set row pins as outputs
    for (int i = 0; i < 4; i++) {
        pinMode(rowPins[i], OUTPUT);
        digitalWrite(rowPins[i], LOW);  // Initially set all rows to LOW
    }
}

void loop() {
    // Light up LEDs in a diagonal pattern (0,0), (1,1), (2,2), (3,3)
    for (int row = 0; row < 4; row++) {
        clearAll();
        digitalWrite(rowPins[row], HIGH);  // Set the current row HIGH
        delay(500);  // Wait for a short period
    }
}

void clearAll() {
    // Set all rows to LOW
    for (int i = 0; i < 4; i++) {
        digitalWrite(rowPins[i], LOW);   // Turn off all rows
    }
}