Some "Sphex" wasps drop a paralyzed insect near the opening of the nest. Before taking provisions into the nest, the "Sphex" first inspects the nest, leaving the prey outside. During the inspection, an experimenter can move the prey a few inches away from the opening. When the "Sphex" emerges from the nest ready to drag in the prey, it finds the prey missing. The "Sphex" quickly locates the moved prey, but now its behavioral "program" has been reset. After dragging the prey back to the opening of the nest, once again the "Sphex" is compelled to inspect the nest, so the prey is again dropped and left outside during another stereotypical inspection of the nest. This iteration can be repeated several times without the "Sphex" changing its sequence; by some accounts, endlessly. Dennett's argument quotes an account of "Sphex" behavior from Dean Wooldridge's "Machinery of the Brain" (1963). Douglas Hofstadter and Daniel Dennett have used this mechanistic behavior as an example of how seemingly thoughtful behavior can actually be quite mindless, the opposite of free will (or, as Hofstadter described it, sphexishness).