Applying the previous instrument, draw three more stripes, having the same parameters:
The Opacity on the layers is of
60% too.
Blending Options-Gradient Overlay
Gradient’s parameters: 
Pick up now the
Ellipse Tool (U) to represent a circle and then press the
Alt button to cut out a circle’s sector, the way it is demonstrated next picture.
Fill 0% on the layers.
Blending Options-Drop Shadow 
Blending Options-Gradient Overlay
