Each of the subdirectories <foo>.d contains files of the following kind:

<foo>n?.tex   -- latex file with slides in beamer format
<foo>n?-notes.tex -- wrapper file to produce handouts
<foo>n?-lec.tex -- wrapper file to produce pdf for the lecture slides

For example, chart.d contains:

chart1.tex
chart1-notes.tex
chart1-lec.tex

and similarly for chart2.tex etc.
