Is it possible to build this grid on :flex?

Question

css

Good afternoon. The bottom line is to build this grid using display: flex;

Answer 1

Well, like this:
https://plnkr.co/edit/cXb13pOCDBfWRJXANL9l?p=preview

Answer 2

For example, like this
https://jsfiddle.net/aw1yykt1/
Well, if for adaptive, you need to think about it, this is for fixed sizes)

Answer 3

It is possible to make as you want through float and all in one parent. I won’t post the solution, it’s too easy, you can handle it yourself.