// Number of pins
#define NUM_PINS 20

// Up, down, left, right
uint8_t PIN_MOVEMENT[][4] {
  // Top row
  {0, 13, 0, 10},
  {0, 12, 11, 9},
  {0, A0, 10, 8},
  {0, A1, 9, 7},
  {0, A2, 8, 6},
  {0, A3, 7, 5},
  {0, A4, 6, 4},
  {0, A5, 5, 3},
  {0, A6, 4, 2},
  {0, A7, 3, 0},

  // Bottom row
  {11, 0, 0, 13},
  {10, 0, 12, A0},
  {9, 0, 13, A1},
  {8, 0, A0, A2},
  {7, 0, A1, A3},
  {6, 0, A2, A4},
  {5, 0, A3, A5},
  {4, 0, A4, A6},
  {3, 0, A5, A7},
  {2, 0, A6, 0},
};

// Top to bottom, left to right
uint8_t PIN_MAPPING[] {
  11,10,9,8,7,6,5,4,3,2,
  12,13,A0,A1,A2,A3,A4,A5,A6,A7
};

// Stores current state of front and back buffers
uint8_t state[][NUM_PINS] {
  {0,1,0,1,0,1,0}, {1,0,1,0,1,0,1,0}
};
bool buffer = 0;

void updateLEDs() {
  for (uint8_t i=0; i<NUM_PINS; i++) {
    Serial.print(state[buffer][i], DEC);
    digitalWrite(PIN_MAPPING[i], state[buffer][i]);
  }
  Serial.println();
}

void setup() {
  Serial.begin(115200);
  for (uint8_t i=0; i<NUM_PINS; i++) {
    pinMode(PIN_MAPPING[i], OUTPUT);
    digitalWrite(PIN_MAPPING[i], LOW);
  }
}

void loop() {
  

  buffer = !buffer;
  updateLEDs();
  delay(500);
}