public Sprite FindSpriteAt(double x, double y, double z)
		{
			int xIndex;
			int yIndex;

			x = Blueprint.x + (int)(Math.Round( (x - Blueprint.x)/GridSpacing)) * GridSpacing;

			if(yOrZ == 'y')
			{
				y = Blueprint.y + (int)(Math.Round( (y - Blueprint.y)/GridSpacing)) * GridSpacing;
				yIndex = (int)((y - (visibleSprites[0][0].y - GridSpacing/2))/GridSpacing);
			}
			else
			{
				y = Blueprint.z + (int)(Math.Round( (z - Blueprint.z)/GridSpacing)) * GridSpacing;
				yIndex = (int)((z - (visibleSprites[0][0].z - GridSpacing/2))/GridSpacing);
			}

			if(yIndex > -1 && yIndex < visibleSprites.Count)
			{
				xIndex = (int)((x - (visibleSprites[yIndex][0].x - GridSpacing/2))/GridSpacing);

				if(xIndex < visibleSprites[yIndex].Count && xIndex > -1)
					return visibleSprites[yIndex][xIndex];
				else
					return null;
			}
			else
			{
				return null;
			}
		}