Tongue-in-cheek, how hard would be to make a captcha? Examples from [1]: Metaphor: Argument is war I shot down his argument He couldn't defend his position

Tongue-in-cheek, how hard would be to make a captcha? Examples from [1]: Metaphor: Argument is war I shot down his argument He couldn't defend his position She attacked my theory Love is a journey: Our marriage is at a crossroads We've come a long way together He decided to bail out of the relationship [1] http://pinker.wjh.harvard.edu/articles/media/2006_09_30_thenewrepublic.html http://pinker.wjh.harvard.edu/articles/media/2006_09_30_then...