#include <FastLED.h> //This is a libeary for the Leds

#define LED_PIN     10
#define NUM_LEDS    16
int offPos;

CRGB leds[NUM_LEDS]; 

void updateLED(int cuPos) {
  offPos = cuPos - 3;
  if (offPos < 0) {
    offPos += NUM_LEDS;
  }
  leds[offPos] = CRGB(0, 0, 0);
  leds[cuPos] = CRGB(255, 0, 0);
  FastLED.show();
}
void setup() { 
  FastLED.addLeds<WS2812, LED_PIN, GRB>(leds, NUM_LEDS); 

}
void loop() {
  for (int i = 0; i <= 16; i++) {
  
  
    updateLED(i);
    
  }
}