When a problem seems intractable, it is often a good idea to try to study "toy" versions of it in the hope that as the toys become increasingly larger and more sophisticated, they would metamorphose, in the limit, to the real thing.

— Doron Zeilberger, Self-Avoiding Walks, the language of science, and Fibonacci numbers (1996)

From a 1996 paper in J. Stat. Inference and Planning.

Topics: simplicity