#include <FastLED.h>

#define NUM_LEDS   4
#define DATA_PIN   2

CRGB leds[NUM_LEDS];

void setup() {
  FastLED.addLeds<NEOPIXEL, DATA_PIN>(leds, NUM_LEDS);
  FastLED.setMaxPowerInVoltsAndMilliamps(5, 500);

  leds[0] = CHSV(96,  255, 255);
  leds[1] = CHSV(160, 255, 255);
  leds[2] = CHSV(0,   255, 255);
  leds[3] = CHSV(35,  255, 255); 
}

void loop() {
  for (int b = 0; b <= 30; b++) {
    FastLED.setBrightness(b);
    FastLED.show();
    delay(3);
  }

  delay(3000);

  for (int b = 30; b >= 0; b--) {
    FastLED.setBrightness(b);
    FastLED.show();
    delay(10);
  }

  delay(3000);
}