View Comments Brandon Zimmermann understands diesel engines, how that perfect mixture of fuel and air, compressed to exactly the right pressure, can ignite with enough force to turn the crank shafts of the machines that move the world. They make sense to him. Not everything else does. Brandon was 6 months old when doctors at Phoenix Children’s Hospital said he suffered a cerebral stroke. “Old people had strokes,” his mother, Nadine, thought. A part of Brandon’s brain was damaged, weakening his left side and leaving him with no left peripheral vision. Doctors predicted he’d be slow to speak and walk. He needed physical, occupational and speech therapy and extra help at school.