Dave Thomas is a renowned programmer and author known for coining the phrases "Code Kata" and "DRY". He recently gave a keynote talk at Empex 2018 about architecture in Elixir projects. Katas and koans are practices for improving programming skills. Katas are simple practice problems while koans reveal underlying truths through questions. Resources for finding Elixir katas and koans include Codewars, Exercism, a GitHub katas repository, and an Elixir koans project.