Topic summary
Pencil of planes
Extracted from the Wikipedia article Pencil (geometry).
Pencil of planes
A pencil of planes, is the set of planes through a given straight line in three-space, called the axis of the pencil. The pencil is sometimes referred to as a axial-pencil or fan of planes or a sheaf of planes. For example, the meridians of the globe are defined by the pencil of planes on the axis of Earth's rotation.