User blog comment:Deedlit11/Googology in Magic: the Gathering/@comment-5150073-20130412144609/@comment-1605058-20130413161014

What I meant is UTM - universal Turing machine. It is, by definition, machine capable of computing anything any other Turing machine can, given input in form we need. We can semi-directly simulate any TM by using one-side infinite tape machine equivalent to one we need and transition rules. Input would be: transition rules, special symbol marking which set of transitions we will take from (i.e. what state we are in), character marking end of input tape and input tape itself. I won't bother to make actual machine, but I hope you can see that this machine could simulate any other. If given proper input