"Whipping a dead horse" etc

Posted by Patty on December 15, 2001

I'm wondering about phrases that mean attempting to do the impossible. "Whipping a dead horse" is a good one, though it refers to something (whipping a horse) that *would* have worked once, but no longer will. "Getting blood from a stone" is another phrase.

Do you have some other good ones? Thanks. - Patty