Why don't we have both? And then some more. It is an awesome REPL with a bit of Excel feel. Runs the code whenever you change it and displays the results in real-time. It is also great for interactive data sources (like web services), where you get the results as soon as they appear upstream. The whiteboard part is super important too. Visual representation is great for design and brainstorming. Even more so, when it provides runtime feedback about your designs. And it gets even more important with collaboration. So at this point we've got a collaborative whiteboard that actually runs the computations. There is, however, one more part to the story. Neither whiteboard, nor a REPL are well suited for implementing the final, production software. We aim to blur the lines between the design and implementation phases, allowing to deploy whatever has just been "sketched".