Here are the instructions for “Vents and Air Conditioners” (part of the DIY series).
There are two rooftop unit, four wall units and fourteen vents in each set
If you don’t know about this series, these sets are for people that want to make their own terrain out of cardboard packaging or odds and ends, and only want a few details to finish things off
http://www.lasercutcard.co.za/shop/scenery/do-it-yourself
