Above is the repeat "quilt" pattern I created by cutting and pasting two sizes of my original cross onto a grid. To get the cross independent of its white background, I clicked on the background with the magic wand tool to select it. Then I chose Inverse under Select to get the cross area which I could then cut and paste into a new document. The new document was first given a background color layer of tangerine, created by selecting the color at the center of my original cross with the eyedropper tool.
In the example above I chose Image - Adjustments - Equalize and the result was a wonderful intensification of the colors.
The example above on the blue background was achieved by Image - Adjustments - Invert. This is a way to achieve dramatic results in one simple step.
I further manipulated the inverted version by replacing the blue under Enhance - Adjust Color - Replace Color.
I started with my original "quilt" and messed about with the gradient adjustment to achieve the lovely spring-like combination of colors shown above.
In the example with the black background I changed the Gradient type to Noise and set Roughness to 56.
The brown and red example above is perhaps my favorite of all the Gradient manipulations.
Here's a more toned-down lighter version. Pretty, but not visually exciting.
Can't quite remember how I achieved this cheerful version, above.
These last two in black and white were done in Image - Adjustments - Threshold. The lighter version above has Threshold set to 117.