not so funny!!

Anyway, an ADJECTIVE circular means having the form of a circle.. for example a circular tower, a circular route or the circular rotation of the earth..

however, the word "CIRCULAR" in CIRCULAR LETTER is NOT an adjective but a NOUN which means for CIRCULATION among a certain group of people or general public.

i hope this is an english lesson for you.

If you are trying to be funny, try a little harder my friend..

tc=)