Synesthesia is a rare neurological condition where sensory paths are crossed in the brain. You might see musical notes as colors, taste textures like “triangles” or “squares” while eating food, or have a sequence-space form in which dates and numbers occupy a spatial location in your mind. The condition has always intrigued me, and I’ve long wanted to write a novel in which the main character experiences the world through this lens. In my latest book, NOT ONE OF US, Jori Trahan has a rare form of synesthesia commonly known as “colored hearing.” For Jori, every person’s voice has particular colors and textures as they speak. This ability ultimately gives her a unique edge to solve an old murder. Jori, like most synesthetes, enjoys her condition; for her, this is just the way the world is. But sometimes the condition can be overwhelming if she is enclosed in a noisy room. In one scene at a crowded bar, the background noise “formed a steady drumbeat of colors that swirled and morphed into blackish splatters of ugly blobs.” Her friend Dana’s voice is the color of “fizzing green arrows” and another character’s voice is “a bruising purple-black, the color of storm…