Two-way nondeterministic finite automaton

A two-way nondeterministic finite automaton (2NFA) is a type of machine that can read multiple symbols at the same time and make decisions about what to do next based on them. It is like a computer that is able to read symbols and decide what to do with them. For example, it might take two symbols as input—say, an 'A' and a 'B'. If the 2NFA sees an 'A', it might decide to go forward and keep reading symbols; if it sees a 'B', it might decide to go backward and read previous symbols. This type of machine can be used to recognize patterns in data or help solve problems.