Picat is a research language intended to combine logic programming, imperative programming, and constraint solving. I originally learned it to help with vacation scheduling but soon discovered its planner module, which is one of the most fascinating programming models I’ve ever seen. First, a brief explanation of logic programming (LP). In imperative and functional programming, we take inputs and write algorithms that produce outputs. In LP and constraint solving, we instead provide a set of equations and find assignments that satisfy those relationships.