This is "Medium Cumos", a handheld kaleidoscope by Japanese artist Minori Yamazaki. The name "Cumos" comes from a combination of 'Cube' and 'Cosmos' and it means universe in a box. Minori Yamazaki designed these scopes around 1980 and they can be described as a polyhedral closed box kaleidoscope. The scope is a white plastic cube with a viewing hole on one corner. The image inside is increadibly delicate and multi-dimensional. the scope measures 3-5/8" x 3-5/8" x 3-5/8" and it is signed (Minori Yamazaki), named (Cumos CM-90), and dated (2021.4.29) by the artist.