Bruce Thompson has published a paper in the American Journal of Physics entitled "Using retrograde motion to understand and determine orbital parameters."
This research was an outgrowth of pondering questions that came up while teaching Astronomy at IC. It emphasizes the geometrical thinking required to fully understand how the planets appear to move from our point of view on Earth.
You can view the entire article by visiting the American Journal of Physics.
https://www.ithaca.edu/intercom/article.php/20051104112006858