Jigsawing a quadrangle from a triangle (Q2871649)

The paper deals with the following construction:NEWLINENEWLINEGiven an acute-angled triangle \(ABC\), construct two isotomic points \(P\) and \(Q\) on \(BC\) and points \(P'\) and \(Q'\) on \(AB\) and \(AC\), respectively, such that \(BPP'\) and \(CQQ'\) are both right triangles that, when rotated about \(P'\) and \(Q'\), respectively, (through appropriate angles) fit with \(AP'Q'\) to form a quadrangle with fourth vertex \(A'\).NEWLINENEWLINEIn addition to show the way to perform the previous construction, the author shows that \(AA'\) passes through the circumcenter of \(ABC\).NEWLINENEWLINEThis reviewer would have appreciated some background and/or motivation for the problem.