Exercise: A typographic jigsaw puzzle

I made some mistakes here. The letter a and q was wrong and I forgot for s. The correct letter a are green circles, the correct letter q are blue circles and red circle is part with foot serif to the right which I did not use. I think it could be part of h or n or m but I am sure. I think this exercise help me better understand how typefaces are constructed and I am able to better see where the differences are between them. Still I am lack of sense (knowledge) why there are so many fonts and how to use them.

 

One thing happened to me after this exercise. When I was writing some notes by my hand I noticed that my handwrite f and t are very similar. I changed the t. I try write it now with foot right serif to make it more readable as t.