The sphere's depth can be changed with the Amplify value. Set it a number less than 100 to get flat buttons (Image 3).

A single light source illuminates the sphere. Its direction and height is contolled at the Direction panel.

Regulate the intensity of the light source with the Brightness Mode.

If you have set another texture as Source Texture, it will be used as sphere material (Image 2). The repetitions of the material on the sphere are controlled with the Tiling values.