Abstracts with ZigZag Filter

1) Open a new document.
2) Select the 'Line' tool. Draw a line. I used 3px, the color does not matter, you can change it later.

3) Go to Filter - Distort - ZigZag. Set your settings similar to mine.

4) Go to Layer - New Fill Layer - Gradient.
Make sure your check 'Group With Previous Layer'.
Choose your gradient settings.
5) Go to Layer - Merge Visible. Now go to Layer - Duplicate Layer.
6) Go to Image - Rotate - Flip Layer Vertical.
7) Select the 'Move Tool' (V). Now, keep pressing the 'down' arrow key on your keyboard until you have something like below.

8) Once again, go to Layer - Merge Visible.
I am going to create a new layer (Layer - New Layer) and then send it to the bottom of my layer stack by going to Layer - Arrange - Send to Back.
9) I am going to fill this layer with black by to Edit - Fill Layer.
10) Merge visible layers (Layer - Merge Visible) and save.