construct line

To draw a straight line from any point to any point.

—Euclid

In classic geometric construction, a line is drawn by scribing a drafting instrument like a pencil or pen along a rule - a stright edge.

In our system, lines are a projection, like a ray of light.

In either case, to construct a line we require two points. Without these two foundational points we can know nothing about the line. It is ungrounded or unfounded.