Changing the color of a shape in a test image

Now that each shape is classified into its group, how would i go about to add color to each shape, each shape must be colored according to group i.e squares all blue, circles all red,but shape that don't fall into the classification should be black in color. I used RGB2 below but i cant add the shapes together into an image with a white background. Is there any other method???

RGB2 = label2rgb(L==n, 'copper', 'w', 'noshuffle');