% returns a pattern
function points = patternEllipse(npoints, firstAxis, secondAxis, noiseCov);

% We create a circle 
thetas=[1:npoints] * 2 * pi / npoints;
circle=[cos(thetas); sin(thetas)];

% Deform the circle to create ellipse
ellipse=diag([firstAxis secondAxis])*circle;

% and then add some noise
points = ellipse + noiseCov * randn(2, npoints);