#include <Adafruit_NeoPixel.h>
#define PIN        2
#define NUMPIXELS 20 

Adafruit_NeoPixel pixels(NUMPIXELS, PIN, NEO_GRB + NEO_KHZ800);
#define DELAYVAL 50 

void setup() {

  pixels.begin(); 
}

void loop() {
  pixels.clear(); 

  for(int i=0; i<NUMPIXELS; i++) {    
    pixels.setPixelColor(i, 250, 0, 250);
    pixels.show();   
    delay(DELAYVAL); 
  }
}