are those boxes and super glue ?

that one

hehe. cats prefer to sit on anything that can be classified itself as already sitting on something.

silly theory: maybe it has to do with static & their coats... prefer not to be electrically grounded?

oh! they are trying to avoid getting struck by lightning!

I don't know how much more insulation a piece of paper adds to a concrete slab, though..

(I'm thinking of one particular cat I knew in one particular living space)

Cardboard does add some insulation.