1. A machine implemented method comprising: executing, by a machine, a computation with a collection of prime directed edges, each prime directed edge being defined as including at least a pairs of execution nodes, the collection of prime directed edges forming a collection of pairs of execution nodes, the machine including at least a memory system for storing data and machine instructions, the data including sequences of symbols, a head for reading the sequence of symbols in the memory system and writing a sequence of symbols to the memory system, and a controller for implementing machine instructions read from the memory system, wherein each pair of execution nodes represents a machine instruction; each execution node has a state of the machine and a sequence of symbols, and is located at a different location in the memory system than the sequence of symbols read; one execution node in the pair of execution nodes represents input of the machine instruction; and the other execution node in the pair of execution nodes represents output of the machine instruction; wherein the machine determines which pair of execution nodes to execute based on the sequence of symbols read.