Blender.java

public class Blender implements Runnable {

  public static final Colour[][][] colours = new Colour[100][100][100];

  @Override
  public void run() {
    var id = new Colour(0, 0, 0);
    for (int x = 0; x < colours.length; x++) {
      Colour[][] plane = colours[x];
      for (int y = 0; y < plane.length; y++) {
        Colour[] row = plane[y];
        for (int z = 0; z < row.length; z++) {
          Colour colour = new Colour(x, y, z);
          colour.add(id);
          if ((colour.r + colour.g + colour.b) % 42 == 0) {
            row[z] = colour;
          }
        }
      }
    }
  }

  public static class Colour {
    double r, g, b;

    Colour(double r, double g, double b) {
      this.r = r;
      this.g = g;
      this.b = b;
    }

    public void add(Colour other) {
      r += other.r;
      g += other.g;
      b += other.b;
    }
  }
}