What are some signs that one might be seeing the three characteristics with more clarity or depth? What might represent that one is having a new and more profound experience of impermanence, dukkha or not-self during one's practice or during any time?
Here are some examples of what is meant by sign:
When we finish sweeping the floor, that might be a sign of impermanence.
If an annoying song keeps repeating in the mind that we can't control then that might be a sign of not-self.
We strongly misidentify the body as the self. If while meditating we see past the concept of the body then we might strangely feel like we have no body at some point. This no body effect might be a sign of not-self.