#include <FastLED.h>
#define BUTTONPIN 3
#define DATA_PIN  2
#define NUM_LEDS  1
CRGB led[NUM_LEDS];

void setup() {
  randomSeed(analogRead(A0));
  FastLED.addLeds<WS2812B, DATA_PIN, GRB>(led, NUM_LEDS);
  FastLED.clear();
  FastLED.setBrightness(255);
  FastLED.show();

  pinMode(BUTTONPIN, INPUT_PULLUP);
  while (digitalRead(BUTTONPIN)); // hold until button pressed
}

void loop() {
  rgbcym();
  // flicker();
}

void flicker() {
  int i = random (63, 255);
  led[0] = CRGB(i, i, i);
  FastLED.show();
  delay(random(63, 255));
}

void rgbcym() {
  for (int i = 0; i < 3; i++) {
    led[0] = CRGB(255 * (i == 0 ? 0 : 1), 255 * (i == 1 ? 0 : 1), 255 * (i == 2 ? 0 : 1)); // CYM
    // led[0] = CRGB(255 * (i == 0 ? 0 : 1), 255 * (i == 1 ? 0 : 1), 255 * (i == 2 ? 0 : 1)); // RGB
    FastLED.show();
    delay(333);
  }
}