A main pipe with three branches coming off it, each coped to fit tight against the outside of the run. The notches at each branch cut into the wall just enough to let the pipe seat flush and square — critical when the branches are close together and the saddle cuts start to interfere with each other.
Open this project in the Pipe Coping Template Generator to pull the cut profiles for each branch. Print them, wrap around your pipe, and scribe the lines — the cope geometry and notch depths are already worked out.