How to make a similar border?

Designer stumped, don't know how to insert between two blocks(like the horizontal splitter) to make it adaptive( or rather resinosa )
in General, here: 5e9be2b786e96807744087.png

HOW? the image of the same paste, is like a harmonica
April 19th 20 at 12:48
3 answers
April 19th 20 at 12:50
Use Gradients or SVG.

Here for example is something like the search results on the website Codepen on request zigzag.

So for example with linear-gradient:

And still a variant with SVG seems like a good solution.
April 19th 20 at 12:52
Without SVG and without pseudo-elements.
Colors are made different for clarity.
You can hardly move for smoothness or to make thicker.
April 19th 20 at 12:54
Can be done using :before/after

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