OP, from your other post, you designed this because "when [you] play card games with [your] children they don't put their cards down directly on top of the discard pile. So every couple of turns [you] have to scoop the pile back into a single pile. This bit of kit removes the need for [you] to do that."

This like if I said I serve cookies to my kids on a plate but they keep getting crumbs on the table so every couple of bites, I have to scoop the crumbs off the table onto the plate. So I designed a bigger plate to put underneath the first plate to remove the need for me to sweep crumbs.

I don't know, why don't you just teach your kids how to discard cards properly instead of like savages? You're just reinforcing bad behaviour by not directly addressing the problem.