Great website! In the video “How to Compose Music 101 – Lessson 5”, you said that according to the “Geometry of Music” chart, you can move to the right. Or you can move to the left only– but only along the arrows.
But towards the beginning of your progression you went from the IV chord to the I chord. This doesn’t have an arrow. This seems to be an exception to the chart’s rule. How do we know what these exceptions are?
You are correct. In reality, there are many different directions you can take a chord that are not considered traditionally “functional”, but they are not wrong. Mostly through good voice leading.
OK, I found your answer in YouTube comments:
I – IV – I would be considered embellishing harmony on the I chord. Both the 3rd and 5th in a I chord can move by step diatonically up, and create a IV chord. It is not considered a functional move though, more decorative.