Pencil (geometry)
= Pencil (geometry)
{wiki=Pencil_(geometry)}
In geometry, a "pencil" typically refers to a collection of geometric objects that share a common property, often associated with points or lines. The most common usage involves a "pencil of lines" or "pencil of rays." \#\#\# Pencil of Lines: A pencil of lines is a set of lines that all pass through a single point, known as the "vertex" or "center" of the pencil.