Rubik's family cubes of all sizes Rubik's family cubes of all sizes The original Rubik's cube was a mechanical 3×3×3 cube puzzle invented in 1974 by the Hungarian sculptor and professor of architecture Ernő Rubik. Extensions of the Rubik's cube have been around for a long time and come in both hardware and software forms. The major extension have been the availability of cubes of larger size and the availability of the more complex cubes with marked centres. The properties of Rubik’s family cubes of any size together with some special attention to software cubes is the main focus of this article. Many properties are mathematical
D-3 (video) format-specific recognition holes. Maximum D-3 runtimes (in the Fujifilm lineup) are 50, 126, and 248 minutes. The D-3 format is now regarded as obsolete. In the 1990s the BBC embarked on a massive project to copy its older video tapes onto D-3, but the D-3 cassettes themselves have become unstable and are being transferred again, although there is doubt over whether the surviving D-3 machines will last long enough to play the 340,000 tapes which the corporation holds. D-3 (video) D-3 is an uncompressed composite digital video videocassette format invented at NHK, and introduced commercially by Panasonic in 1991 to