This is a tileable green circuit build for the early game. With yellow belts and assembly machine 2's, it can be tiled three times before it becomes starved for copper.
I don't remember who came up with this design originally, but please add a comment below if you know. I've been using it for a long time, since 0.13.
Red belt version: https://factorioprints.com/view/-Kl-cSRdWCenc8Q3Qqv4