Designer, implementor, user, writer A Fragment by Donald Knuth dl.acm.org Thus, I came to the conclusion that the designer of a new system must not only be the implementor and the first large-scale user; the designer should also write the first user manual. The separation of any of these four components would have hurt TeX significantly. If I had not participated fully in all these activities, literally hundreds of improvements would never have been made, because I would never have thought of them or perceived why they were important. Eating your own dog food making
In terms which must be altered [Life] frequently sets its problems in terms which must be altered if the problem is to be solved at all. Dorothy Sayers, The Mind of the Maker UnfoldingCo-Evolution of Problem and Solution Spaces in Creative Design life