How to make quadrilateral with 4 points in matlab

Given 1 reference point and 3 other points. How can I code for constructing a quadrilateral using these 4 points.

Answer 1

[Walter Roberson]

http://www.mathworks.com/matlabcentral/fileexchange/20266-quadmesh-quadrilateral-mesh-plot?focused=6119310&tab=function

Or

plot([x1 x2 x3 x4 x1], [y1 y2 y3 y4 y1])

or

area([x1 x2 x3 x4], [y1 y2 y3 y4])