byte ledA = 3;
byte ledC = 4;

const byte N_COLS = 4;
const byte N_ROWS = 4;

byte rowPin[N_ROWS] = { 0, 1, 2, 3 };

byte matrixState[4][4] = { { 1, 0, 0, 1 },
                           { 0, 0, 0, 0 },
                           { 1, 0, 0, 1 },
                           { 0, 1, 1, 0 }};

void setup() {

  pinMode(ledA, OUTPUT);
  pinMode(ledC, OUTPUT);
  

}

void loop() {
  delay(240);
  digitalWrite(ledA, 1);
  digitalWrite(ledC, 0);
  delay(240);
  digitalWrite(ledA, 0);
  digitalWrite(ledC, 1);
}

void matrix(byte ri, byte ci) {
  for ( byte r = 0; r < N_ROWS; r++ ) {

    for ( byte c = 0; c < N_COLS; c++ ) {
    }
  }
}