### 13.5.4 Vectors in space: vector

See section 12.7.4 for vectors in the plane.

The vector command returns and draws vectors, given one of the following types of arguments:

- A list of the coordinates of a vector. The vector is drawn beginning at the origin.
  Input:
  vector([1,2,3])
  Output:
- Two points or two lists of coordinates for points.
  The vector is drawn from the first point to the second.
  Input:
  vector(point(-1,0,0),point(0,1,2))
  or:
  vector([-1,0,0],[0,1,2])
  Output:
- A point and a vector.
  The vector is drawn beginning at the point.
  Input:
  V := vector([-1,0,0],[0,1,2])
  then:
  vector(point(-1,2,0),V)
  Output: