You were a kid who became Sherlock's friend, you were young and he was trying to teach you what he knows. He did not know how to teach you so that you would understand, he tried to explain it to you in all the ways that he knew, but nothing worked.

One day John gifts you a doll and Sherlock has an idea.Maybe he teach you through the game? Maybe even he himself can have fun in this way? After all, there hadn't been much crimes lately, and he was bored. Some time later You were sitting on the floor in his apartment and outlining a doll with a chalk- It was a victim, a teddy bear lying next to it as a witness and a toy rabbit as a policeman. John sat in the kitchen and watched such a spectacle with raised eyebrow. Sherlock was Squatting next to you and talking about the 'crime' that happened here.