Although I agree it might be easier to make with an algorithm, you could make it by hand.
Looking at the puzzle itself, it appears that it’s just this shape repeated over and over:
Which is just 4 octagons with 5 squares. Note that I made the red squares overlap the octagons a bit.
You can then tile them or copy and paste them to make a pattern like this:
Once you have that, you can select individual octagons and squares that are connected, and do “path->Union” to unify them. Once you’ve done that enough times, you end up with something like this:
Now repeat this 100 times, and you have a puzzle.
Here is the SVG I used to make this example. I did not use clones, but rather duplicated and moved the original shape. So there are a few of them that are not exactly aligned.
If I was to do this for real, I would probably use the Edit -> Clone -> Create Tiled Clones option to make sure everything was properly aligned (and then make sure to unlink clones before you try and Union them).