Spoilers ahead, watch the video first ;)
If you watch the ad again, you can appreciate the quiet subtlety with which it shows its hand: It’s less of a reveal than a call to be more attentive. The opening scene, for example, focuses not on the teacher but on what she is holding: An image of a piece of art depicting a woman. This image is flipped at the end to reflect how easily we can be fooled once we’ve looked at something, decided what it is, and moved on.Here’s the making-of video: