Take two flat plates and if they are really flat, you can “wring” them together and they will stick to each other. Here, I’ve got two cast iron plates I’ve machined and lapped (100 grit sandpaper on a flatish surface) with some WD40 on them. They are 5″ x 7″ and weight 1,224 grams (2.7 pound) each.
Pressed them together with a twist and they are “Look Ma! No hands!” stuck. They slide about with a frictionless feel but don’t want to separate unless you slide them apart.
While they are flat, they aren’t particularly smooth (100 grit scratches and milling marks) so the light oil is key to a long lasting stick.