plot points in a different colour co ordinates

 x = randi([-35,165],[2000,1]);
      x = x';
      y = randi([-20,80],[2000,1]);
      y = y';
      plot(x,y,'kx','LineWidth',2,'MarkerSize',10)
I can also plot points with different colours within two circles.

      num1 = 2000;
      radius = 30;
      theta = rand(1,num1)*(2*pi);
      r = sqrt(rand(1,num1))*radius;
      xCor = r.*cos(theta);
      yCor = r.*sin(theta);
      plot(xCor,yCor,'rx','LineWidth',2,'MarkerSize',10)
      subplot(1,1,1)
      hold on;
      num = 1000;
      rad = 10;
      theta = rand(1,num)*(2*pi);
      r = sqrt(rand(1,num))*rad;
      xCor2 = r.*cos(theta);
      yCor2 = r.*sin(theta);
      plot(xCor2,yCor2,'gx','LineWidth',2,'MarkerSize',10)

Thanks...

[Walter Roberson]

This looks to me to be exactly the same discussion as is taking place in Andy's question http://www.mathworks.co.uk/matlabcentral/answers/63990-plot-points-in-a-different-colour-depending-on-co-ordinates