Via Adopt @ https://www.thoughtworks.com/radar/techniques

4. NoPSD
'Just In Time Design' is an important and useful concept for visual design that the NoPSD movement attempts to capture. You don't need to design the whole application or every UI element up front. Design things as you need them with as lightweight tools as you can use. We have seen a corresponding growth in simpler tools with faster learning curves, such as Sketch, as well as an increasing return to pen-and-paper (especially when paired with an existing robust digital style guide). Because of the limitations of flat mock-ups when you’re designing for screens, creating prototypes of varying fidelity with tools such as Invision, FramerJS and Origami - or simply HTML/CSS and a bit of JavaScript - has also become increasingly common and valuable for communicating design intent.