./pdfjoin --outfile all.pdf lec0.pdf lec1.pdf lec2.pdf lec3.pdf lec4.pdf lec5.pdf lec6.pdf lec7.pdf lec8.pdf lec9.pdf lec10.pdf lec11.pdf lec12.pdf;
#./pdfnup -W5.5in -H4in -4 all.pdf all-4.pdf;
./pdfnup --nup 2x2 --outfile all-4.pdf all.pdf;

