Explaining the solution for this treetop area puzzle

After failing numerous times on this puzzle, this is the solution I found when looking up solutions for this puzzle.

I don't get the answer at all. I can't see how it makes sense. These are my attempts at solving it previously:

This is my understanding of this puzzle so far, so I may be wrong since I'm obviously not getting the solution:

• Rectangular blocks of different colors must not share the same area with rectangular blocks of a different color -- in this case, the white square blocks cannot share space with the black square blocks.
• The spiky blocks are immune to the color rule, but they must pair up with another spiky block. As seen in the first image, the puzzle below has two spiky black balls sharing space with the white squares, and that is a valid solution.

So this is my question: how does this solution work? Why don't my solutions fit the criteria? The way I see it, my solutions have separated the white blocks from the black blocks, and I've isolated the black spike on its own since it has no partner

Your understanding of the square symbols is correct: they fail if they share a region with a square symbol of any other color. Non-square symbols don't matter in the least.

However, your understanding of the spiky symbols is slightly off. The spiky symbol must share a region with exactly one other symbol of the same color (but any kind of symbol is fine). Symbols of other colors don't matter at all. I think this is the first puzzle where it matters that the other symbol isn't necessarily another spiky symbol.

The spikey block needs to be paired up, regardless of if it has a partner. So in this case, it needs go get paired up with a regular black block to meet its requirement.