Zuse’s thesis is the idea that the Universe could be running within a digital computer. It was formulated by Konrad Zuse in Rechnender Raum (Calculating Space) in 1969. The computer could be a very large Cellular automaton according to Zuse.
A computer program to simulate our Universe (and all the others)
Systematically create and execute all programs for a universal computer, such as a Turing machine or a CA; the first program is run for one instruction every second step on average, the next for one instruction every second of the remaining steps on average, and so on.
/Juergen Schmidhuber in (Schmidhuber 1999)
The need for interlacing computations like this is to avoid the halting problem if we were to wait for any of these programs to finish.