Actually, that's quite a trick.
Most of the holes I'm familiar with are round. That's a quality that they seem to be graced with. Not only that, fitting holes into pegs, even when the pegs are square and the holes are round, is a bit difficult. Obviously I intended to write something along the lines of fitting pegs into holes - a rather commonplace and overused metaphor. It seems that it was so common that I didn't even think about (or copyread) what I was writing.

Go to: It' can't be that difficult, or
Go to: Something much