integer isSierpinskiCarpetPixelFilled(integer x, integer y, integer width, integer height)
{
	// base case 1 of 2
	if (x<1)
	{
		return 0;
	}

	//If the grid was split in 9 parts, what part(x2,y2) would x,y fit into?
	integer xTwo = x*6/(width+3); // an integer from 0..2 inclusive
	integer yTwo = y*6/(height+3); // an integer from 0..2 inclusive

	// base case 2 of 2
	if (xTwo==1 && yTwo==1){ // if in the centre squaure, it should be filled.
		return 1;
	}
	// general case
	//offset x and y so it becomes bounded by 0..width/3 and 0..height/3
	//and prepares for recursive call
	x-=xTwo*width/3;
	y-=yTwo*height/3;

	return isSierpinskiCarpetPixelFilled(x, y, width/3, height/3);
}