I would comment that, when one realizes the unmoving mind, wind can move, flag can move, mind can move again and there is no problem ... for all is unmoving moving. [monk]
the Gateless Gate, Case 29. It was a custom in the old days in China that as a guest speaker arrived to offer a teaching at a Temple, the Temple flag would be raised. Master Hui-Neng, the Sixth Patriarch, was to offer a talk and as he approached he heard two monks deep in discussion: the wind is moving, no the flag is moving, and on and on.
Hui-Neng says,'neither the wind nor the flag is moving: it is your mind that is moving.'
A commentator, Mumon, adds 'neither the wind, the flag, nor the mind, moves: all of their words fail.'