Take the expression
to symbolize the perspective from a room A of a middle room B and a far room C.
Now step from room A into room B, from which the perspective is
And now room C, with perspective
Symbolize such perspectuality by
A(B(C)) =p B(A)(C) =p C(B(A))
Such forms, expressions, perspectives and equations are what this book is about.
FP is available as free PDF from Lulu.com, scribd.com and academia.edu (it doesn't display correctly on the last two but the PDFs download fine).
FP is also available as a POD 8x11 paperback at Lulu, with a deliberately-provocative cover.