Ctesibius (Ktesibius) of Alexandria (285-222 BC), Ancient Greek mathematician and inventor who studied pneumatics. Woodcut. On the left Ctesibius sits in his room surrounded by objects he is studying, showing his interest in the sound produced by columns of air at different lengths. On the right his father shampoos a client's hair while on the wall hangs his son's adjustable mirror. From Architechtur .. Mathematischen .. Kunst by Gaultherius Rivius (Nuremberg, 1547). Woodcut. .