Drawings on books purchased with iBooks Say I buy a book using iBooks (OS X Yosemite on a MacBook Pro). Using iBooks, I can highlight text and add notes. What about drawing shapes? e.g. circles, squares, arrows, etc. 

If this is not possible with iBooks itself, is there any way to open a book bought with iBook on a different app with more editing support?
If your books are really PDFs, and there are no security restrictions, you could use Adobe/Acrobat Reader with its commenting tools.