Answer:
Often found in doctor's offices and pirate flags
Nothing specific, but more than a few. This many clustered, together will do.
The day is their night and the night is their day, when I shout and they shout back I run away.
MT_TF_S What are the missing letters? Why?
I go around in circles, But always straight ahead Never complain, No matter where I am led.
If itβs information you seek, come and see me. If itβs pairs of letters you need, I have consecutively three. What am I?