We stayed in Mirador Mansions back in 2010. You entered through a hallway and took the elevator to the 7th floor. As you exited you went towards the central atrium. Looking over the railing it seemed like doors, floors, air-con units repeated endlessly whether you looked up or down. This seemed like the leftovers of Kowloon Walled City.

“The most densely populated City on Earth had only one postman. His round was confined to an area barely a hundredth of a square mile in size. Yet within that space was a staggering number of addresses: 350 buildings, almost all between 10 and 14 stories high, occupied by 8,500 premises, 10,700 households, and more than 33,000 residents.”……(https://www.atlasobscura.com/articles/kowloon-walled-city)

Isometric projection done with Sakura Micron pens and watercolour on an 11x14 sketchbook.