  * Control the Arduino.
  */
 void loop() {
+
     // Check if a button switch was pressed.
     int simonLed = getSimonLed(analogRead(BUTTONS));
     if (DEBUG) {

        Serial.print(analogRead(BUTTONS));
        Serial.print(", ");
        Serial.println(simonLed);
    }
}


    // The switch is not active.
    return -1;
}


/**
 * Cycles LEDs on and off in a decorative pattern while waiting for player input.
 */
void playLightShow() {

    // Cycle lights.
    for (int i = 0; i < QTY; i++) {

        // Get the last position in the array.
        int last = QTY - 1 - i;

        // Turn off previous lights.
        if (i-1 >= 0) {
            digitalWrite(LEDS[i-1], LOW);
            digitalWrite(LEDS[last+1], LOW);
        }

        // Turn on current lights.
        digitalWrite(LEDS[i], HIGH);
        digitalWrite(LEDS[last], HIGH);

        // Wait before cycling the next set of lights.
        delay(LIGHT_DELAY);
    }

    // Turn off final set of lights.
    digitalWrite(LEDS[0], LOW);
    digitalWrite(LEDS[QTY-1], LOW);
}
