Christmas projection mapping ideas don't need a big house or a big budget. The best ones use something you already have, a box, a window, a door, and fit light to its exact shape so it looks like part of the decoration rather than a picture thrown at a wall. In the clip beside this article, two plain cardboard boxes become wrapped presents with nothing but a projector and an iPhone running EasyMapper Studio.
Here are eight ideas, roughly from easiest to most ambitious. Each one uses the same steps: add a layer per surface, drag its corners onto the real edges, then play something festive on it.