Koan

On Saturday night we ran into a friend who posed us this paradox: can God create a knot that He cannot untie?
On Sunday we visited a friend, an excellent painter, in her studio, and she showed us a book of koans that inspired her work.
Then I thought of a paradox of my own.
Buddhism teaches that the self is an illusion, a mental construct. When you reach enlightenment, not a likely occurrence, you'll understand that about your "self."
So, if the self is an illusion, how can art be based on self-expression?
Or perhaps the illusion that we are ourselves is so powerful that it enables the illusion that is art.