Here's a technique you can modify to create a variety of interesting objects and backgrounds. After creating a bark-like pattern, we'll use the Polar Coordinates filter to manipulate the effect.
STEP 1
Open a new document. We'll demonstrate with a 400x400 RGB
image. Fill with the color of your choice. This green (RGB 0/184/0)
will produce a Matrix-esque final result.

STEP 2
Like many filters in Photoshop, the Polar Coordinates requires
some color variation with which to work. (If we applied the
filter to this solid color image, there would be no apparent
effect.) The filter Noise> Add Noise is often used, but
this time we'll use the filter Artistic> Film Grain
with the settings Grain: 20, Highlight Area: 10, and Intensity:
5.

STEP 3
To make these areas of different color larger and more distinct,
we'll apply the filter Pixelate> Crystallize, using
a setting of Cell Size: 8.

STEP 4
A Blur> Motion Blur filter using an angle of 90 degrees (vertical)
and a distance of 20 pixels gives us streaks. We can now create
a more distinct pattern by applying a rather substantial Unsharp
Mask. The settings here are Amount: 360%, Radius: 70 pixels,
Threshold: 0 levels.
STEP 5
Now it's time to play! Filter> Distort> Polar Coordinates,
set to Rectangular to Polar gives us a great look.
STEP 6
However, that's not where we're heading (just yet).
Command-Z (Mac) or Control-Z (Windows) will undo the filter.
Do that now. Command-Option-F (Mac) or Control-Alt-F (Windows)
re-opens the Polar Coordinates dialog box. Do that. Now click
the Polar to Rectangular button, followed by OK.
STEP 7
Image> Rotate Canvas> 90 degrees CW. Now apply Polar Coordinates
with the Rectangular to Polar option.
STEP 8
Again use Image> Rotate> 90 degrees CW, followed by Polar
Coordinates using the Rectangular to Polar option. Remember that
you can apply the last-used filter with the last-used settings
through the keyboard shortcut Command-F (Mac) or Control-F (Windows).
Use that shortcut three more times.
Re-applying Polar Coordinates with Rectangular to Polar will additional times on this image changes the highlights and shadows without producing a noticeable effect on the shapes. Rotating the canvas 180 degrees and re-applying Polar Coordinates with the Rectangular to Polar options produces a variety of interesting shapes.
Needless to say, this is just a starting point. Rotate commands can be added among the Polar Coordinates filters. Additional filters and adjustment layers can be applied to make the look truly your own.







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