Take the 2-minute tour ×  How can one determine the position of
a symbol on the typeset page? Possible uses:    • One page
contains a fill-in-the-blanks text, and the opposite page
contains only the solution words, each starting at the same
position on the page where the blank started. The blanks on the
first page should all be of equal length in order to not reveal
any information. It can be assumed that the solution expressions
don't overlap (and if they do, one can still manually adjust).
• relative anchoring: One has typeset a complex diagram or
equation, and one then creates a series of transformations. For
example, diagram 2 is like diagram 1, but with the complex
middle portion simplified so that one can focus on other parts;
the relative positioning of certain outer elements of diagram 1
should be the same in diagram 2 to help the reader understand
which diagram elements correspond. For this one would need to be
able to obtain the coordinates of certain outer elements so that
one can subtract them.