An FFGL mixer that puts the layer below behind a sheet of glass and this layer on a hidden screen reflecting in it, the way Pepper's ghost has worked since 1862: a Victorian pane, a Musion-style foil or the plastic pyramid people stand on a phone. The sheet reflects what Fresnel says it does at every pixel's angle and lets the rest through, so the ghost only ever adds light, vanishes at Brewster's angle under polarised light, doubles in a thick pane and shimmers on a foil that rings like a drum. A second plugin, SW Pepper Feed, lays a clip out for a real pyramid.
This demo runs the plugin's shaders and a port of its CPU half in your browser, so it needs JavaScript and WebGL2. The plugin itself, its source and its downloads are on its repository.