Take an hammer and some nails, fix the nails and try to
make a piece of wood go through all the nails. You'll get a B spline...
Spline [n.] : A flexible strip (wood or rubber) used in drawing curved lines.
a set of points that influence the curve's shape
control points that lie on the curve
curve passes through the control points knots
control points merely influence shape
convex polygon boundary that encloses a set of control points
If some data points are used to construct a curve the
curve can either pass through the points, in which case the curve is interpolating,
or the points can just be used to control the general shape of the curve and
the curve doesn't actually pass through the points, in which case the curve