A man sitting at a table wears a red sweater while two glasses of water rest on the table ; one glass is half empty .
There is a third glass that is invisible to the naked eye .
A man sitting at a table wears a red sweater while two glasses of water rest on the table; one glass is half empty.
There is a third glass that is invisible to the naked eye.
A third glass cannot be invisible.
A third glass can not be invisible .