Add paper data layout

This patchset adds contents to the section "Data layout" which describes the internal structure of the set in more detail.
For me, compiling with `pdflatex main.tex`, the upper line results in

`[...] several buckets --like in [...]`

instead of

`[...] several buckets -- like in [...]`

Which I guess should be there. Notice the space after the double-dash (`--`)!