http://books.google.com/books?id=uSHqAAAAMAAJ&printsec=frontcover&dq=B%C3%BCchlein+von+der+Fialen+Gerechtigkeit&source=bl&ots=_FABRmQscv&sig=8Tp639UHFMaAKZkOxYah4RuxdX4&hl=en&ei=YXdcTMmOGcKnsQbbtvGPBg&sa=X&oi=book_result&ct=result&resnum=1&ved=0CBIQ6AEwAA#v=onepage&q&f=false

this might be useful to some of you. It's in German, Fraktur script at that, so you can't all read it I know, but it does have many useful diagrams. This book was printed in 1486 in Germany by a master builder named Matthäus Roritzer, and it is about Ad Quadratum geometry. It is an instructional manual on how to use this system