A complete tutorial on how to make this abstract wallpaper.
Open a new file that would have 1024x768 px and 72 dpi. Then make use of this instrument
to represent the lowest background of the file.

Blending Options-Gradient Overlay

Gradient?s parameters:

Selecting
the previous instrument, we have to draw now an inclined stripe, colored in 10161C.

on the layers we should have

Represent the same way several other stripes, having the same color, but a different width.
Open a new file that would have 1024x768 px and 72 dpi. Then make use of this instrument
to represent the lowest background of the file. 
Blending Options-Gradient Overlay

Gradient?s parameters:

Selecting

on the layers we should have

Represent the same way several other stripes, having the same color, but a different width.