How to add custom rectangle shapes or images on the detected / tracking objects in opencv python?

I wish to add a cool rectangle shapes / images for my tracking objects that their centroid point will be same with the rectangle centroid location of the detected object or the tracking object, that is similar what we see in the movies or tv series (such as “Person of Interest”)

Colored Boxes


I will be very happy if someone would guide me about how to achieve such feature with opencv python. Most of examples I have seen made with java versions; but I couldn’t find any solid example with opencv python version, thank you.