Complex shape border in css?

Question

css

What is the best way to make such a block border?

Answer 1

the best is svg
like this for example: https://codepen.io/topicstarter/pen/NYLBGY
since I don’t know the topic of svg thoroughly, I asked a question to specialists in the field of svg and an answer is expected: https://ru.stackoverflow.com/q /809836/33274

Answer 2

SVG or Canvas (draw in memory and paste into the block as a background).