Variable Geometry aircraft have moveable lifting elements that can be reconfigured. Swing-wings are one example. I've also made extendable trailing edges, telescoping spans and variable geometry canards and strakes. These can be for show. However, if they are well designed, stiff and lightweight, they can actually add more performance than you lose due to the extra weight, drag and complexity.

I've also made hinged control surfaces, which allow elevator trim adjustments without the drag and paper warping and weakening from bending the paper.