May I suggest a replacement phrase for an old classic? I'm sure you've heard,
"You can't fit a square peg into a round hole?"
Referring of course to attempting to do something that just won't work. You might have heard your grandpa say it, or your mechanic. I have an equally profound phrase to replace that one.
But it's important to say it the right way. Say it like you work in a Nascar pit crew. Or like you're an extra on Smokey and the Bandit. Or like your from where I grew up. (Much love to my beautiful valley!) Get real twangy with it.
"Well shoot, that sure ain't gonna work. That's like tryin to fit two babies in the same cupboard!"
I think it's going to catch on...