Simple closed path: through every points, does not intersect itself



Method: order points according to £c to an anchor point

How to find £c=tan-1 (y/x)? £c= tan-1 (y/x) ¡ô in (I) ¶H­­ <=> y/x ¡ô in (I) ¶H­­ <=> 0 ¡Ø y / (x + y) ¡Ø 1 ¡ô in (I) ¶H­­ i.e., Program t := y / |x| + |y|; (0, x = y = 0) if x < 0 then (II, III) t := 2 ¡V t; else if y < 0 then (IV) t := 4 ¡V t; 0 ¡Ø t ¡Ø 4 0 ¡Ø 90t ¡Ø 360