Mapping neural networks in brain, retina and spinal cord requires (1) comprehensive parts lists (vertex types), (2) nanometer scale connection detection (edge types), and (3) millimeter scale network tracing. Connectomics based on high-resolution automated transmission electron microscope imaging merges these operations and allows discovery of network modules and motifs as well as the their geometric patterning cell shapes. The mammalian retina contains ≈ 70 classes of neurons assembled into ≈ 15 different network modules, with significant motif overlap. We analyzed mammalian retinal connectome RC1 to unpack this mesh of neurons. A key question that emerges in tracing networks is how neurons and patterns are regulated. I will describe the scales and modes of patterning (packing, tiling, covering) adopted by different neurons and discuss the implications for developmental regulation.