The website linked: > Declarative Dragging What if making a diagram draggable was as simple as specifying what it can become? Drag-and-drop makes the digital graspable. But designing bespoke drag interactions involves a lot of fiddly code to handle geometry, feedback, and animations. As a result, many people, from educators to game designers, mathematicians to creative tool builders, often don't bother. Declarative dragging inverts the problem. Rather than programming all that visual behavior directly, you simply say, for each element you want to make draggable, which future states of your application dragging it should lead to. Our system speculatively renders those states to work out where things can go, then combines these possible worlds into a smooth, responsive drag-and-drop interaction. Our goal with this project is to let people keep working within the semantic worlds they inhabit, while helping them turn the rules of their worlds into rich tactile interactions in ours.