module building where


data Platform : Set
data Building : Platform → Set

data Platform where
    ground : Platform
    extension : (p : Platform) → Building p → Platform

data Building where
    onTop : (p : Platform) → Building p
    hangingUnder : {p : Platform} → (b : Building p) → Building (extension p b)

firstBuilding : Building ground
firstBuilding = onTop ground

firstPlatform : Platform
firstPlatform = extension ground firstBuilding

secondBuilding : Building firstPlatform
secondBuilding = onTop firstPlatform

hangingBuilding : Building (extension firstPlatform secondBuilding)
hangingBuilding = hangingUnder secondBuilding