I found this visualization regarding homotpy in wikipedia:

https://commons.wikimedia.org/wiki/File:Homotopy_curves.png

I would be very grateful if you could explai me all the abbreviations being used. I guess t stands for t and s for space, so that H (t,s) would be a homotopy in time t and space s. But what does gamma stand for, a given homotopy path? Would we call x and y the origo points of the homotopy?

Thanks in advance.