a necker cube is an example of a(n)
Necker cube The Necker cube is an optical illusion first published as a rhomboid in 1832 by Swiss crystallographer Louis Albert Necker.[1] It is a simple wire-frame drawing of a cube with no visual cues as to its orientation, so it can be interpreted to have either the lower-left or the upper-right square as its front side. Necker cube is used in studies of human visual perception.
Rubik's Cube In the mid-1970s, Ernő Rubik worked at the Department of Interior Design at the Academy of Applied Arts and Crafts in Budapest.[15] Although it is widely reported that the Cube was built as a teaching tool to help his students understand 3D objects, his actual purpose was solving the structural problem of moving the parts independently without the entire mechanism falling apart. He did not realise that he had created a puzzle until the first time he scrambled his new Cube and then tried to restore it.[16] Rubik obtained Hungarian patent HU170062 for his "Magic Cube" in 1975. Rubik's Cube was first called the Magic Cube (Bűvös kocka) in Hungary.