// https://wokwi.com/projects/420120497546844161
// https://forum.arduino.cc/t/toggling-between-two-pairs-of-leds/1341607

# include <ezButton.h>

const byte greenLed = 12;
const byte redLed = 10;

ezButton button(2);

bool greenNow;

void setup() {
  pinMode(greenLed, OUTPUT);
  pinMode(redLed, OUTPUT);

  digitalWrite(greenLed, HIGH);
  digitalWrite(redLed, LOW);
  greenNow = true;

  button.setDebounceTime(21);
}

void loop() {
  button.loop();

  if (button.isPressed()) {
    greenNow = !greenNow;

    digitalWrite(greenLed, greenNow ? HIGH : LOW);
    digitalWrite(redLed, greenNow ? LOW : HIGH);
  }
}