01 · Indoors, seen from outside
Snow and Santa in the window
Project from inside, seen from the street
Hang a white sheet, shower curtain or sheer white fabric tight across the inside of the window and project onto it from the room. People outside see falling snow, Santa's sleigh or a gingerbread parade in the window while the room behind stays hidden.
Map a shape to the window so the scene stays inside the frame; for an arched or odd-shaped window, trace it with an Outline shape. Keep the room dark, because any light behind the fabric washes out the image. A small projector is enough: 300 ANSI lumens after dark, or 1,000+ on a bright street or at dusk.