For my essay I have chosen to do it on Star Trek: The Next Generation. I will be researching into why things look the way they do. For a start, why do all the Federation ships all look similar? They all feature a saucer section and most of them always have two warp nacelles (two long engines at the back of the ship). A couple have four, but they rarely feature one or three and are always symmetrical.
I will need to find why Gene Roddenberry came up with this idea.
Excelsior class (top) Galaxy class (bottom). Both with saucer and two warp nacelles.
Oberth class. slightly different design, but still shares the same features by having a saucer section and two symmetrical warp nacelles.