Find initial expression that a reduction process with 2 rules does not terminate

Imagine a language of finite sequences of 0 and 1. The rules for simplifying strings in this language are given by: l??x => x1101 0??x => x00 In these rules, the variable x denotes an arbitrary sequence of 0s and Is and the sign '?' denotes a single 0 or 1. Construct an expression for which the reduction process does not terminate. I have across this problem in "Introduction to Functional Programming" by Richard Bird, and I can't find the solution. Can someone guide me on the methology to solve this?...Read more