This is just a request for clarification, an attempt to penetrate the notation.
Is this what you have in mind? If so: (1) the operation is not definite,
any point $P_{k+1,j}$ on the circle arc between $P_{k,j}$ and $P_{k,j+1}$ forms a
right angle; and (2) the subsequent polygons could be nonconvex.
But perhaps I am misinterpreting...
<br />&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;![ngon right angles][1]


  [1]: https://i.sstatic.net/Wzynb.jpg