Could someone give an example of this pic?

Since Fourier transform and inverse Fourier transform for one qubit is only Hadamard gate, for two qubit case following two circuits are equivalent.

First circuit (Fourier transform applied on qubit $q_0$)

First circuit (inverse Fourier transform applied on qubit $q_1$)

Both circuits return state

$$ |psirangle = frac{1}{2}(|00rangle + |01rangle + |10rangle - |11rangle). $$

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EDIT: I have just realized that the gate $F$ is general unitary transformation and not the QFT (I was missleaded by F = Fourier). However, my example is also valid. It is a particular case for two qubits asked for in the question.