Very interesting interview with the writer / director of this documentary.
For the cubic
with three real roots, the roots are the projection on the x-axis of the vertices A, B, and C of an equilateral triangle. The center of the triangle has the same abscissa as the inflection point.
I first saw talk about electronically tuneable glasses in 2012. The company involved appears to have given up. ( check my work ). But it is too attractive of a field of work to be left alone. It is suggested electronically tuned lenses may be used for lense replacements in cataract surgery.