Parabolic and BESSER interpolation using the three successive points M, O, and P. Dotted line: parabolic interpolation may create a spurious extremum between points M and O. Solid line: interpolation using our BESSER method with continuous derivative at point O. The control points of the intervals, whose y-coordinates are denoted by c_M and c_P, define tangents to the Bézier splines in their endpoints. The x-coordinates of the control points are located at the center of the corresponding intervals.