Beyond NP: A More Intuitive Complexity Problem

The author challenges the use of the Halting Problem as the canonical example of a problem harder than NP-complete, arguing it's confusing and unintuitive. While undecidable, verifying a "yes" answer for the Halting Problem can be done by running the program for a finite number of steps. A more easily understandable alternative is presented: moving a token on an infinite grid to reach a target point. This problem is PSPACE-complete in lower dimensions, but its complexity explodes with increasing dimensions, eventually reaching ACKERMANN-completeness, visually demonstrating a complexity far beyond NP problems.