If you view this oddly named but fascinating Video on the topic of how ONE Man unintentionally managed to kill more people on this planet through the intentional introduction of Tetra-Ethyl LEAD into fuel mixtures to slow down combustion rates inside 4 stroke Engines using Spark Ignition Systems, a useful by-product comes with the VOP's perfect explanations discussing Compression, Pre-Ignition, Engine Knock and many other aspects adding to our understanding of how ALL Fuel Octanes are created by mixing together differing ratios of Only Two Different Fuels: Normal-Heptane and Iso-Octane: