Continuous Round Trip

Aka WalkingSkeleton: The system starts being fully connected from almost the first day, so that each part grows in function, but all the parts always continue to work together

Or: A form of IncrementalDelivery, where the first delivery is done early in development.

An example may be the C3 payroll, which read input, computed checks inadequately, and produced output, almost from the very beginning. Much of the development consisted of adding another input, improving the computation to use it, and enhancing the output.