#include <FastLED.h>
#define NUM_LEDS 100
#define DATA_PIN 3

CRGB leds[NUM_LEDS];

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

void loop() {
  for (int i=0; i<NUM_LEDS; i++){                
    leds[i] = CRGB(random(0, 256), random(0, 256), random(0, 256));
    FastLED.show();
    delay(10); 
    leds[i] = CRGB(random(0, 64), random(0, 64), random(0, 64));

    FastLED.show();
  }
}