MOD inner connector short

Short inner connector that is used with
-All non diagonal housings
-cross bar housing
** This is part of a project i'm doing for uni. The concept is all about re-using old/scrap materials. I've designed a series of connectors that aim to join old scrap pieces into new furniture/homewares.
The idea is that scrap material can be slotted into the inner connector (the diameter of the hole can be changed) and then these connectors slotted into the housing.
The different housings can be used interchangeable to create different objects. The scale of the connectors can also be played with to create new things.