I go away for five minutes, and when I come back someone had knocked it over:
Perhaps I should explain myself. This model (link to source) seems to start at the bottom and build up. But the first layer, Remember, looks to me to be a poor start to a lesson. Some present experience - an image, a video, manipulatives - that embody things learnt before would be a much better starting point. The very question, "Do you remember when we learnt about..." seems to me to suggest forgetting.
Luckily the makers of this diagram have actually built the instability of the model into the picture!
Perhaps I've got it wrong, and misunderstood the whole thing. If you think so, let me know.