Two views of nested sequences of projective structures —
From this journal in April 2013:
From the arXiv in September 2014 —
Saniga's reference  is to a paper submitted to the arXiv in May 2014.
My own note of April 30, 2013, concludes with an historical reference
that indicates the mathematics underlying both my own and Saniga's
The exercises at the end of Ch. II in Veblen and Young's
Projective Geometry, Vol. I (Ginn, 1910). For instance: