private int[] computeSkirt(TPoint[] points, int width) {
		int[] skirt = new int[width];
		for (int i = 0; i < width; i++) {
			//impossibly high value 
			int minY = 5;
			for (int j = 0; j < points.length; j++) {
				TPoint currentPoint = points[j];
				// if point is in right column
				if (currentPoint.x == i) {
					if (currentPoint.y < minY) minY = currentPoint.y;
				}
			}
			skirt[i] = minY;
		}		
		return skirt;
	}