debuscope

from The Century Dictionary.

• noun A double mirror, composed of two polished surfaces placed at an angle of 70°, used like a kaleidoscope to repeat a pattern or other object.
• noun It was invented by M. Debus, a French optician, and is used in preparing geometrical decorative designs. Also called chromeidoscope.

from the GNU version of the Collaborative International Dictionary of English.

• noun (Opt.) A modification of the kaleidoscope; -- used to reflect images so as to form beautiful designs.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun A form of kaleidoscope.