In his Philosophical Investigations Wittgenstein used games as an example of a class of activities that resist definition in terms of necessary and sufficient conditions, but instead are tied together only by a criss-crossing network of similarities, or family resemblances. However in his book The Grasshopper (1978) Canadian philosopher Bernard Suits provided a plausible definition covering all and only games: ‘To play a game is to engage in activity directed towards bringing about a specific state of affairs, using only means permitted by rules, where the rules prohibit more efficient in favor of less efficient means, and where such rules are accepted just because they make possible such activity.’