   bool anyInvalid = false;
   bool anyEmpty = false;
   bool anyWallConstrainsViolated = false;
+  int switchesOn = 0;
   for (int index = 0; index < GRIDSIZE * GRIDSIZE; index++) {
     int row = getRow(index);
     int col = getCol(index);
     if (isWall(row, col)) {
       continue;
     } else if (isSwitchOn(row, col)) {
+      switchesOn++;
       if (illuminationCount(row, col) > 1) {
         anyInvalid = true;
         setColor(row, col, RED);  // Conflicting lights.

#define YELLOW rgb_color(255, 255, 0)
#define OFF rgb_color(0, 0, 0)

// TODO(bhomberg): update pin numbers
// LiquidCrystal lcd(12, 11, 5, 4, 3, 2);

PololuLedStrip<2> leds;
rgb_color colors[STRIP_LENGTH];

#define SWITCH_ON 1
#define SWITCH_OFF 2


// Arduino setup() and loop()
void setup() {
  isVictorious = false;
  isHot = false;
  isBad = false;
  isEmpty = false;
  badAttempts = 0;
  
  if (USE_SERIAL) {
    Serial.begin(9600);
  }
  pinMode(LED_BUILTIN, OUTPUT);

  pinMode(22, INPUT);
  // Initial switch pins as INPUTs.
//  for (int switch_index = 0; switch_index < GRIDSIZE * GRIDSIZE; switch_index++) {
//    int pin = getSwitchPin(getRow(switch_index), getCol(switch_index));
//    if (pin != NO) {
//      pinMode(pin, INPUT);      
//    }
//  }
  
  // PololuLedStripBase::interruptFriendly = true;

