#define PIN 25
#define NUMPIXELS 52

#include "Adafruit_NeoPixel.h"

int del = 500;
Adafruit_NeoPixel strip = Adafruit_NeoPixel(NUMPIXELS, PIN, NEO_GRB + NEO_KHZ800);

void setup() {
  strip.begin();
  strip.setBrightness(80);
  strip.clear();
  strip.show();
}

void loop() {
int i;
  for (i = 0; i < NUMPIXELS-1; i++) { // red
    strip.setPixelColor(i, strip.Color(0xFF, 0, 0));
    strip.show();
    delay(del);
    strip.setPixelColor(i, strip.Color(0, 0, 0));
    strip.show();
  }
    strip.setPixelColor(NUMPIXELS-1, strip.Color(0, 0xFF, 0));
    strip.show();
    delay(del);
    strip.setPixelColor(NUMPIXELS-1, strip.Color(0, 0, 0));
    strip.show();

  for (i = NUMPIXELS-1; i > 0; i--) { // red
    strip.setPixelColor(i, strip.Color(0xFF, 0, 0));
    strip.show();
    delay(del);
    strip.setPixelColor(i, strip.Color(0, 0, 0));
    strip.show();
  }
    strip.setPixelColor(0, strip.Color(0, 0xFF, 0));
    strip.show();
    delay(del);
    strip.setPixelColor(0, strip.Color(0, 0, 0));
    strip.show();
}