// Output:
// left 0 right 255
// left 0 middle 255 right 15

void setup() {
  Serial.begin(115200);

  {
    uint8_t x      = 0;
    uint8_t left   = x % 16;
    uint8_t right  = (x-1) % 16;

    Serial.print(" left ");
    Serial.print(left);
    Serial.print(" right ");
    Serial.print(right);
    Serial.println();
  }

  {
    uint8_t x      = 0;
    uint8_t left   = x % 16;
    uint8_t middle = x - 1;
    uint8_t right  = middle % 16;

    Serial.print(" left ");
    Serial.print(left);
    Serial.print(" middle ");
    Serial.print(middle);
    Serial.print(" right ");
    Serial.print(right);
    Serial.println();
  }
}

void loop() {}