The Woodpecker Method was introduced in the book Pump Up Your Rating (Google Books) by GM Axel Smith (FIDE), who was inspired by a training method used by GM Hans Tikkanen (FIDE), who used it to improve his chess. A subsequent book The Woodpecker Method (Google Books) was published by the two GMs.
A description of this method is given in Brian Towers's answer, but it involves repeatedly solving tactics problems (not only what's the best move? But, also, what are the critical lines?).
There's some debate online (see e.g. chess.com) as to whether this helped Axel Smith improve, or if this was attributable to other aspects of his chess training. Hence my question:
Question: Has anyone other than GM Axel Smith and GM Hans Tikkanen had success improving their chess through the "Woodpecker Method"?