(The CW, 8 p.m.): It’s been a long road for Barry Allen. First he was just a normal extremely young CSI professional for a fictional police department, and then he got zapped by a particle accelerator and became the Flash. Then he figured out how to time travel, and then he time-traveled really badly and screwed everything up, and then a bunch of other stuff happened and he developed other super-speed-related powers. Flash-punches! Flash-wall-climbing! Flash-pancake-making! Here we are many seasons later and Barry Allen is still developing new super-skills, and tonight’s is one that might have come in handy back when he was accidentally flashpointing John Diggle’s kid out of existence: speed-thinking!