'A' pour complete. 'B' pour awaiting arrival of the concrete truck.
One of the inevitable conditions arising in urban construction is the need to underpin adjacent building foundations. For the uninitiated, underpinning is a process whereby you support your neighbor's building with a new deeper footing beneath their existing footing because your bottom of footing needs to be lower than the neighbor's.
In this case it's a relatively straightforward process to support a minor load from the the adjacent single story warehouse next door.
Duplexellence 3.0 is on its way.