It is about the end of the movie Inception, with that spinning wheel that was not let to stop in the end, leaving the end as open whether to know the hero has come back to reality or is still dreaming.
The explanation was found here
-there is a cam play to draw the attention to the left hand of the hero (the left hand is made hard to see when the hero dreams)
-when the left hand is observed, it shows that it sports a wedding ring when the hero dreams and none when he is in reality.
The hero did not accept his wife is dead and uses dreaming as a way to keep her alive.
-in the last scene, his left hand sports no wedding ring so he is in reality. He managed.