What does a turn look like in music?
Similarly, what does a trill look like in music?
The trill (or shake, as it was known from the 16th until the 19th century) is a musical ornament consisting of a rapid alternation between two adjacent notes, usually a semitone or tone apart, which can be identified with the context of the trill (compare mordent and tremolo).
Similarly, how do you write a turn in music?
Turns can be performed after the written note, or instead of it, depending on where they are written. A turn written directly above a note replaces that note. A turn written after the note should be performed after the note is sounded. Turns can be written using any note value which is basically fast.
Forgive me for stating the obvious, but a trill is a rapid alternation between adjacent pitches, up either a half step or whole step from the notated pitch (never down).