#include <Adafruit_NeoPixel.h>
#define PIN 6
#define NUMPIXELS 256

Adafruit_NeoPixel pixels(NUMPIXELS, PIN, NEO_GRB + NEO_KHZ800);
float angle = 0;
int cube[8][3] = {
  {-1, -1, -1}, {1, -1, -1}, {1, 1, -1}, {-1, 1, -1},
  {-1, -1, 1},  {1, -1, 1},  {1, 1, 1},  {-1, 1, 1}
};

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

void loop() {
  pixels.clear();
  float sina = sin(angle);
  float cosa = cos(angle);
  
  for (int i = 0; i < 8; i++) {
    float x = cube[i][0];
    float y = cube[i][1] * cosa - cube[i][2] * sina;
    float z = cube[i][1] * sina + cube[i][2] * cosa;

    int px = (int)(x * 8 + 8);
    int py = (int)(z * 8 + 8);

    if (px >= 0 && px < 16 && py >= 0 && py < 16) {
      pixels.setPixelColor(py * 16 + px, pixels.Color(255, 255, 255));
    }
  }

  pixels.show();
  angle += 0.02;
  delay(50);
}