How to do it on flex?

Question

css

There is such a grid on the desktop,
it is necessary that on the mobile phone it becomes like this
grid on flex,
tell me pliz!

Answer 1

order on flex

Answer 2

https://codepen.io/topicstarter/pen/bvzvWp?editors=0100 something didn't work for me without an ax

Answer 3

Alternatively https://codepen.io/Lina_A/pen/bvzjLw?editors=1100