Beautiful and pretty are often taken to mean the same. But they are different.
Pretty refers to the external beauty of a female. A pretty girl may not be beautiful.
Beautiful implies a degree of softness and delicacy. It includes admiration for the inner goodness of a female.

Similarly, there is a little difference in the words Discover and Invent.
Discover is to find out something which has always existed but has not been known.
Columbus discovered America.
Invent is to find out something which has never existed before.
Thomas Edison invented the light bulb.