#include <Adafruit_NeoPixel.h>

#define PIN        6
#define NUMPIXELS 300
#define DELAYVAL 50

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

uint16_t start = 0;
uint8_t r = 255;
uint8_t g = 0;
uint8_t b = 0;

void setup() {
  pixels.begin();
  Serial.begin(9600);

}

void loop() {

  if (r > 0 && b == 0) {
    r--;
    g++;
  }
  if (g > 0 && r == 0) {
    g--;
    b++;
  }
  if (b > 0 && g == 0) {
    r++;
    b--;
  }

  Serial.print("R: ");
  Serial.print(r);
  Serial.print(" G: ");
  Serial.print(g);
  Serial.print(" B: ");
  Serial.println(b);


  Serial.print("Start: ");
  Serial.println(start);

  pixels.setPixelColor(++start % NUMPIXELS, pixels.Color(r, g, b));

  pixels.show();
  delay(DELAYVAL);

}