I created web tool to generate seamless patterns - https://www.arbuuz.com/draw/index.html
To cgenerate seamles pattern you need PNG file or files.
The first image is generated with this web tool and the second image is created from the first image. Elements in image is created with Blender and rendered images are saved as transparent PNG files. Background added in Photoshop.
The second image created from generated seamless pattern.
You can generate backgrounds for Blender scenes. There are some samples that you can do with this web tool - https://www.arbuuz.com/draw/index.html
Interesting! Did you explored more with 3D shapes?
a little bit
Super useful!
What does the processing / calculation speed depend on?
Better to use smallest images as a source symbols in generated image instead of divider from 1 to 10. You can change divider but if you use source image already divided in Photoshop then it will be faster to calculate.
If you were so inclined, you could make this into a native app (compiled for different platforms) and charge $$ for it. 
Or a Photoshop plugin or something.
I already used it for part of a job earlier. I looked around for similar things earlier, but couldn’t find something just like it. Photoshop has a built-in “Random Fill” tool, but doesn’t have the same options this does.
