four color

int y1 = A0;
int x2 = A1;
int y2 = A2;
int x1 = A3;

int ledPin0 = 2;
int ledPin1 = 3;
int ledPin2 = 4;
int ledPin3 = 5;

void setup() {
  Serial.begin(9600);
  pinMode(ledPin0, OUTPUT);
  pinMode(ledPin1, OUTPUT);
  pinMode(ledPin2, OUTPUT);
  pinMode(ledPin3, OUTPUT);
}

//pinMode(ledPin0, OUTPUT);

int readX() {
  pinMode(y1, INPUT);
  pinMode(x2, OUTPUT);
  pinMode(y2, INPUT);
  pinMode(x1, OUTPUT);

  digitalWrite(x2, LOW);
  digitalWrite(x1, HIGH);

  delay(5); //pause to allow lines to power up

  return analogRead(y1);
}

int readY() {

  pinMode(y1, OUTPUT);
  pinMode(x2, INPUT);
  pinMode(y2, OUTPUT);
  pinMode(x1, INPUT);

  digitalWrite(y1, LOW);
  digitalWrite(y2, HIGH);

  delay(5); //pause to allow lines to power up

  return analogRead(x2);
}

void loop()

  int x = readX();
  int y = readY();


  if (y > 510 && x > 520 && x < 940 && y < 940)
  {
    Serial.println("a");
    Serial.println(y);
    digitalWrite(ledPin0, LOW);
    digitalWrite(ledPin1, HIGH);
    digitalWrite(ledPin2, HIGH);
    digitalWrite(ledPin3, HIGH);
  }
  else if (y > 510 && x < 510)
  {
    Serial.println("b");
    digitalWrite(ledPin0, HIGH);
    digitalWrite(ledPin1, LOW);
    digitalWrite(ledPin2, HIGH);
    digitalWrite(ledPin3, HIGH);
  }
  else if (y < 500 && x > 520)
  {
    Serial.println("c");
    digitalWrite(ledPin0, HIGH);
    digitalWrite(ledPin1, HIGH);
    digitalWrite(ledPin2, LOW);
    digitalWrite(ledPin3, HIGH);
  }
  else if (y < 500 && x < 510)
  {
    Serial.println("d");
    digitalWrite(ledPin0, HIGH);
    digitalWrite(ledPin1, HIGH);
    digitalWrite(ledPin2, HIGH);
    digitalWrite(ledPin3, LOW);
  }
  else if (x > 1000 && y > 1000)
  {
    Serial.println("NOOOOOOONE");
  }

  delay(100); //just to slow this down so it is earier to read in the terminal - Remove if wanted

}