Block Side

Hello. I am writing from a translator, I apologize in advance.

In the new update, the ability to expand the block was added, rotation on the position of the player.
However, I cannot, in logic, determine the direction of the world in which the block is looking.

Take a simple example.
We put a block. He will always look at the player during installation. After clicking the right mouse button, behind the installed block, a block of stone should appear. How to do it?

I can not find a way to take action.
I can not even take the coordinates of the location of the player who interacts with the block, in order to establish some kind of logic to the location of objects relative to the cardinal points

I would be grateful if you give a hint, or an answer, is it possible to somehow determine the block direction in the world, where the block is looking?