Thanks for the reply @BramVanroy.
However, when you say



 BramVanroy:

the output will N*768


this means that the output of each transformer of the final hidden layer will be N*768 or the “combined” output of all transformers in the final hidden layer?
I think that my problem concern the fact that BERT, in every hidden layers, uses a number of transformers encoder equal to the number of tokens in input.
In the image, if we have N tokens, so for each hidden layer we have N Encoders.
But if each Encoders outputs a value of shape N*768, so there is a problem.
P.S.: just to clarify, I use the term Hidden Layer to indicate the “Trm” horizontal blocks between the input and the output.
In the image, the hidden layer size is 2.