ABSTRACT
To encourage creativity, people often say, “Think outside the box.” The recommendation urges divergent thinking, a break from common rules and assumptions. Murray Gell-Mann, a Nobel laureate in physics, believes that the phrase originates from the popular nine-dots puzzle, where the solver has to cross all the dots with no more than four straight lines without lifting the pen [1] (Figure 6.1). The puzzle is impossible to solve if the lines stay inside the box (outlined by the dashed square in Figure 6.1). But once you go beyond the box, the solution becomes almost trivial.
