Here is one way:
N= 12; % Number Of Sides To Polygon
a = sort(rand(N,1))*2*pi;
r = randi(9, N, 1);
x = cos(a).*r;
y = sin(a).*r;
figure(1)
plot([x; x(1)], [y; y(1)])
This creates a randomly-shaped polygon. Change it to produce the sort of shape you want.
