#case 1 => There is common area. merge case
my @poly1 = ([0,0],[0,2],[2,2],[2,0],[0,0]);
my @poly2 = ([0,0],[3,0],[3,1],[0,1],[0,0]);
my @merge_poly12;
print ("@merge_poly12\n"); #then I want to print [0,0],[0,2],[2,2],[2,1],[3,1],[3,0],[0,0];

#case 2 => There is not common area, No merge
my @poly1 = ([0,0],[0,2],[2,2],[2,0],[0,0]);
my @poly3 = ([3,0],[3,2],[4,2],[4,0],[3,0]);
my @merge_poly13;
print ("@merge_poly13\n"); # then I want to print nothing or only @poly1.

#case 3 => There is not common area, But have line, Merge case
my @poly1 = ([0,0],[0,2],[2,2],[2,0],[0,0]);
my @poly4 = ([0,2],[0,3],[1,3],[1,2],[0,2]);
my @merge_poly13;
print ("@merge_poly14\n");  # then I want to print [0,0],[0,3],[1,3],[1,2],[2,2],[2,0],[0,0]