#include <FastLED.h>
CRGB leds[8];


void setup(){
  FastLED.addLeds<WS2812B, 42, GRB>(leds, 8);
}
void loop(){
  leds[0]=CRGB::Black;
  leds[1]=CRGB::Black;
  leds[2]=CRGB::Black;
  leds[3]=CRGB::Black;
  leds[4]=CRGB::Black;
  leds[5]=CRGB::Black;
  leds[6]=CRGB::Black;
  leds[7]=CRGB::Black;
  FastLED.show();

  delay(500);

   leds[0]=CRGB::Red;
  leds[1]=CRGB::Black;
  leds[2]=CRGB::Black;
  leds[3]=CRGB::Black;
  leds[4]=CRGB::Black;
  leds[5]=CRGB::Black;
  leds[6]=CRGB::Black;
  leds[7]=CRGB::Black;
  FastLED.show();

  delay(500);
}