Step-1, take a new document with the dimension of 5 inches
by 5 inches and click ok.
Step-1, select he rectangle tool and create a new square
box.
Step-3, select and Keep the fill color black then go to
effect menu-Stylize-Round Corner and keep the Radius to 0.5 inch with the
preview checkbox then click ok.
Step-4, select and make two copies of the shape and set them
aside.
Step-5, now start working with the first shape with select
and go to gradient palate and keep the gradient palate type radial.