 We will also have to make some assumptions about the configuration of the tape when the machine is started, and when it finishes, in order to interpret the computation. We will assume that if the function to be computed requires n arguments, then the Turing machine will start with its head scanning the leftmost ‘1’ of a sequence of n blocks of ‘1’s. The blocks of ‘1’s representing the arguments must be separated by a single occurrence of the symbol ‘0’. For example, to compute the sum \(3+4\), a Turing machine will start in the configuration shown in  Figure 3.