Cycler
1RB0LB_1LB1LC_0RC1RA (bbch), which has period 18 and preperiod 4.A cycler is a Turing machine that eventually enters a repeating cycle. Such a Turing machine runs forever and thus is a non-halting Turing machine. A cycler may be seen as a special case of a translated cycler which has offset zero.
The rule for identifying cyclers is simple:
û → û
where û is any headed tape segment.
See also
- Translated cycler
- Section 2 of bbchallenge's deciders write-up.