isrectangle

This function takes a set of vertices defined by the vectors X and Y and returns true if they form a rectangle and false otherwise.

X and Y do not need to be sorted, but it is assumed that X(i) is paired with Y(i).

You can also call the function with one input Z, such that Z = [X(:),Y(:)].

For examples, check out the test suite for the following Cody problem:
http://www.mathworks.com/matlabcentral/cody/problems/2671-check-if-vertices-form-a-rectangle