A New Kind Of Reversal

But look carefully, with \(d=10\), \(r=\sqrt{\cfrac{d}{x}}\)

which section of the Horn should it be?  Maybe, a cup formed by rotating the r-axis arm, sucks energy into the cup instead and directs the energy down the apex.  In which case, \(x\) and \(r\) is swapped; a new kind of reversal.

May God help us all...