Turing Machines

A Turing machine is a model of what a computer can solve, and what it cannot solve.

The machine contains a tape, which is infinite in both directions.

Visualization of a Turing Machine tape.

Visualization of a Turing Machine tape.

$$\text{([if state] [if value] [set value] [set state] [move direction])}$$

There are two main reasons why an instruction is invalid.