// Level 2: one red light runs along the strip.
#include <Adafruit_NeoPixel.h>

const int stripPin = 6;
const int ledCount = 10;
Adafruit_NeoPixel strip(ledCount, stripPin, NEO_GRB + NEO_KHZ800);

void setup() {
  strip.begin();
  strip.setBrightness(40);
}

void loop() {
  for (int index = 0; index < ledCount; index++) {
    strip.clear();                                         // all LEDs off
    strip.setPixelColor(index, strip.Color(255, 0, 0));    // LED number index: red, green, blue
    strip.show();
    delay(30);
  }
}