Create a new document, let it be 150x120px, the color of the background: white. Also, make sure that the color of the first plan is black and the background white. Now all u need is to make a switch using Gradient Tool and start by pulling from the upper right edge to the bottom left edge, like it is shown in the picture.
Filter Difference Clouds
Inverzija (Ctrl+I)
Use Filter>Render>Difference Clouds and right after that invert the given picture (Ctrl+I).
To get something from the light contrast use Levels (Image> Adjustments> Levels option or a shourtcut Ctrl+L). Then pull the left handle (shadowing) to the place from where grafic starts. In the space gamma (Input Levels in the middle) put in: 0.33. Like it is shown in the picture down.
Click Ok.
And at the end go to Image> Adjustments> Hue/Saturation (Ctrl+U) and click on Colorize. In the space Hues put in the meaning of 235 and click Ok.
While constructing this effect don't hope that you will get the same effect again but with trying you can come to many different and intersesting details.
Gradient Tool
