ABSTRACT
Matt wants to connect the nine dots shown in Figure 6.1 by four straightlines without lifting his pen or pencil from the paper. (The solution to the problem appears in Figure 6.2, but do not peek until you too have worked on the problem for at least 2 minutes.)
At first, like nearly everyone who comes across this problem for the first time, Matt assumes that the nine dots comprise a rectangle and that he can’t go outside
the box formed by the dots. But this self-imposed rule dooms all attempts to solve the problem. It is only when he questions the assumption that he must stay within a set of invisible boundaries, and recognizes that the task allows greater freedom than he’d initially assumed, that he can step outside the frame of his own making and deal with the problem effectively (Figure 6.2).
