In operation, the starting point is a given tape with a finite sequence of symbols prewritten on it, a given program, and the Turing Machine head over the leftmost symbol on the tape in state 1. At each step, the head reads the symbol in the current cell, then follows the instruction in the row corresponding to that symbol and the current state. There are three parts to the instruction: | In operation, the starting point is a given tape with a finite sequence of symbols prewritten on it, a given program, and the Turing Machine head over the leftmost symbol on the tape in state 1. At each step, the head reads the symbol in the current cell, then follows the instruction in the row corresponding to that symbol and the current state. There are three parts to the instruction: |