Agreed. Knuth no doubt chose a simple, but non-trivial, program to build from scratch to illustrate the technique. McIlroy responded with an equivalent made up

Agreed. Knuth no doubt chose a simple, but non-trivial, program to build from scratch to illustrate the technique. McIlroy responded with an equivalent made up from Lego bricks. Knuth documented what he did. McIroy said "I used this command" n times.