Overview
The Air Duct is a wallpaper added during the Block Party event. It resembles a darker shade of Grey Wallpaper in the inventory, but when you place two next to each other, they form a continuous pattern that inserts 'steel joints' like shown on the right picture.
In-Game Description
Sneak around in these to find the secret documents. Nobody knows why they build them human-sized!
Rarity: 15
To grow, plant an Air Duct Seed. (Or splice a Dark Grey Block Seed with a Grey Block Seed)