Stephenson:Neal:The System of the World:307:Time stops

From the Quicksilver Metaweb.

Saturn is describing "flow", a mental state common among computer programmers and mathematicians. The state is entered when the problem you are working on overwhelms all other external factors, and can result in extraordinary bursts of productivity.

For a more thorough explanation of Flow by Mihaly Csikszentmihalyi, and its application to learning by gifted students, see this article at the University of Chicago.