Jim Weirich gave us many things. Among his last was Wyriki, a small Rails app described in his own words as an 'Experimental Rails application to explore decoupling app logic from Rails.' Many of us paid our final respects to Jim on his last commit to this project. Now it's time to learn from it. In this talk we'll explore how Jim applied the principles of Object Oriented Design to achieve his goals of decoupling; look at how he used decoupling to speed up testing; how decoupling improved and simplified his tests; and look at his design style. Jim's legacy leaves a lot to learn from, let's do it.