Portfolio Stereoscope Positive Postcard format Primus Perfect Prismatic lens Prismatic-square-type Projection Pseudoscope Pseudoscopy Quirolo, Antonio R. F. Rack-and-pinion Radieux-Stéréo Reflecting stereoscope Refracting stereoscope Relief Revolver-Stereobetrachter Revolving stereoscope Rice patent Richard, Jules Richmond/Stern patent Roche patent Rotating stereoscope Rotoscope Schneider viewing case Screen process Scultoscope Semilens Septum Short-focus lens Sibley patent Single-view stereoscope