> If someone doesn't quickly and intuitively grasp that a shape is a collection of faces, ..., I'm not sure that they have what I am personally looking for

I was doing the same to weed out the bad candidates - asking them something they should know, something logical and basic - but got bad feedback once, been asked to instead focus my questions on the strong points described in the CV. I mean, for the practical part the candidate wasn't able to count the unique words in a text file in 30 minutes. I thought opening files and reading strings and splitting are so basic anyone should know them.