54F3

I don't think it's possible to get a #000 hole and #FF0 box without something to up the contrast, so let's wait on this.
Let's leave and go where the slots take us again.

It's possible. The "hole" has a lower blue value than the rest of the box. If the blue slider is lowered by the value of the "hole", it will be black and the box will be dark blue. Of course, you're all assuming a keyhole painted on in black will work as an actual keyhole.