Parabola construction

Check the first box and use the slider to go through the geometric construction of a parabola: 0) the lines tangent to the parabola at the points it intersects the closing string will intersect on the vertical centerline of the parabola at twice the height of the parabola above the closing string; 1) a parallel line to the closing string is tangent to the apex of the parabola; 2-6) constructing the quarter and eighth points of the parabola.
Check the second box to overlay the geometric construction of the tangents to the points of the parabola.
Check the third box to overlay the construction of the parabola using a funicular polygon. The parabola is a continuous curve that is tangent to the midpoints of the segments of the funicular polygon.