#include <Adafruit_NeoPixel.h>
#define PIN        21
#define NUMPIXELS 16

Adafruit_NeoPixel pixels(NUMPIXELS, PIN, NEO_GRB + NEO_KHZ800);

void setup() {
  // put your setup code here, to run once:
  pixels.begin();
}

void white_color(){
  int i=0;
    for i in range (16) :
      pixels.setPixelColor(i-1, pixels.Color(0, 0, 0));
      pixels.setPixelColor(i, pixels.Color(255, 255, 255));
}

void red_color(){
  pixels.setPixelColor(0, pixels.Color(255, 0, 0));
  pixels.setPixelColor(1, pixels.Color(255, 0, 0));
  pixels.setPixelColor(2, pixels.Color(255, 0, 0));
  pixels.setPixelColor(3, pixels.Color(255, 0, 0));
  pixels.setPixelColor(4, pixels.Color(255, 0, 0));
  pixels.setPixelColor(5, pixels.Color(255, 0, 0));
  pixels.setPixelColor(6, pixels.Color(255, 0, 0));
  pixels.setPixelColor(7, pixels.Color(255, 0, 0));
  pixels.setPixelColor(8, pixels.Color(255, 0, 0));
  pixels.setPixelColor(9, pixels.Color(255, 0, 0));
  pixels.setPixelColor(10, pixels.Color(255, 0, 0));
  pixels.setPixelColor(11, pixels.Color(255, 0, 0));
  pixels.setPixelColor(12, pixels.Color(255, 0, 0));
  pixels.setPixelColor(13, pixels.Color(255, 0, 0));
  pixels.setPixelColor(14, pixels.Color(255, 0, 0));
  pixels.setPixelColor(15, pixels.Color(255, 0, 0));
  pixels.setPixelColor(16, pixels.Color(255, 0, 0));
}

void loop() {
  // put your main code here, to run repeatedly:
  //red_color();
  white_color();
  pixels.show();
  delay(200);
  
  pixels.clear();
  delay(200);
}