Students use their heads. Supercomputer users do it in parallel Superman does it faster than a speeding bullet. Surfers do it standing up. Surgeons do it incisively. Swimmers do it in the water.
Swimmers do it under water.
Swimmers do it with strokes. System programmers do it in overlays. Systems Programmers do it with pointers. Tailors make it fit. Taxi drivers do it all over town.