We might say roughly that the unlimited cases are characterized by this: that they are not played with a definite supply of numerals, but instead with a system for constructing numerals (indefinitely). When we say that someone has been supplied with a system for constructing numerals, we generally think of either of three things: a) of giving him a training similar to that described in 30), which, experience teaches us, will make him pass tests of the kind mentioned there; b) of creating a disposition in the same man's mind, or brain, to react in that way; c) of supplying him with a general rule for the construction of numerals.