#include <Adafruit_NeoPixel.h>>

#define PIN 25
#define NUMPIXELS 16
Adafruit_NeoPixel pixels(NUMPIXELS, PIN, NEO_GRB + NEO_KHZ800);

void setup() {
  pixels.begin();
  pixels.show(); 
}

void loop() {
  for(int i=0; i<NUMPIXELS; i++) {
    pixels.setPixelColor(i, pixels.Color(255, 0, 0)); // Red color
    pixels.show();
    delay(500);
    pixels.setPixelColor(i, pixels.Color(0, 0, 0)); // Turn off
    pixels.show();
    delay(500);
  }

}