This was #1. When developing Siege, it’s clear to see this was the first map they had created. Therefore this oozes everything Siege, and R6 potentially stands for – CQC, an Urban setting, and a reliance on communication. Originally, where defenders were allowed outside, the construction site opposite the house was to be used as well. Check out the E3 Launch of Siege to see – https://gaming.youtube.com/watch?v=6wlvYh0h63k
