This chapter discusses the analysis of the connectome of the fly optic lobe, focusing on the identification and classification of neuronal cell types and their connectivity rules. The authors aim to complete the list of intrinsic cell types in the optic lobe and understand their roles in visual processing. They find that most new cell types contain 10 to 100 cells and integrate information over medium distances in the visual field. The study reveals several new families of interneurons, including a serpentine medulla (Sm) family with more types than any other. The authors use high-dimensional feature space analysis and algorithms to validate the consistency of cell types and hypothesize about their functional roles in motion, object, and color vision. They also quantify connectivity with boundary neurons that connect the optic lobe to the central brain. The connectomic approach, which defines cell types based on similar connectivity patterns, is shown to be effective in reducing the complexity of the connectome and providing insights into brain function and development. The chapter highlights the importance of connectivity in distinguishing cell types and interpreting their functions, and discusses the implications for visual processing in flies.This chapter discusses the analysis of the connectome of the fly optic lobe, focusing on the identification and classification of neuronal cell types and their connectivity rules. The authors aim to complete the list of intrinsic cell types in the optic lobe and understand their roles in visual processing. They find that most new cell types contain 10 to 100 cells and integrate information over medium distances in the visual field. The study reveals several new families of interneurons, including a serpentine medulla (Sm) family with more types than any other. The authors use high-dimensional feature space analysis and algorithms to validate the consistency of cell types and hypothesize about their functional roles in motion, object, and color vision. They also quantify connectivity with boundary neurons that connect the optic lobe to the central brain. The connectomic approach, which defines cell types based on similar connectivity patterns, is shown to be effective in reducing the complexity of the connectome and providing insights into brain function and development. The chapter highlights the importance of connectivity in distinguishing cell types and interpreting their functions, and discusses the implications for visual processing in flies.