Dexion

A brand of slotted steel "angle iron" which has been used to construct display panels for a con art show. Within fandom, the brand name, Dexion, was used generically to refer to any slotted angle iron. Largely superseded by use of tubular conduit.

For a period, Dexion was a cult object in some parts of fandom.

Instructions on how to build an art show with it