Looking for an oddball part

[TheGreatSatan]

When I worked at a retailer we had these small (1/2 inch) things that clamped two pieces of cardboard/paper together. They are small and look like a capital letter 'H'. Each open end are pinched off, so you can clip them on one piece of cardboard then slide another piece in next to it and it'll hold them nearly flush together.

I have no arty ability, but here's the jist of it. Have you ever seen anything like them?

or

I want to get some so I can clamp my 200mm fans to the edges of the plexi in Project Boom Tube.

[TheGreatSatan]

Actually I think these plastic hair pins will work too