#include <FastLED.h>
#define NUM_LEDS 2
#define DATA_PIN 21
CRGB leds[NUM_LEDS];
void setup() { 
    FastLED.addLeds<NEOPIXEL, DATA_PIN>(leds, NUM_LEDS);  // GRB ordering is assumed
    FastLED.setBrightness(255);
}
void loop() { 
  leds[0] = CRGB(100,0,0); //CRGB(Red,Green,Blue)
  FastLED.show();
  delay(500);
  leds[1] = CRGB(0,100,0);
  FastLED.show();
}