loop-hole
131Group (mathematics) — This article covers basic notions. For advanced topics, see Group theory. The possible manipulations of this Rubik s Cube form a group. In mathematics, a group is an algebraic structure consisting of a set together with an operation that combines …
132Movie projector — This article is concerned with technical aspects of moving film projection. For non film movie projection, see digital cinema. For historical aspects, see the article history of cinema. 35 mm movie projector in operation …
