Hi George, Thanks for this highly informative session! What do you think of the following design focused iteration algorithm? This is an attempt at creating a variation on the TDD work flow: Red: design & specify the outsider view of an API (includes designing the domain model) Green: design & implement the insider view of the API (includes designing the static run time structure ie: the object role interactions in DCI parlance) Refactor: tinker & optimise the API