Terracota D-uplo compatible Shingle roof, variable size and shingle tilt

Update: Some small bugfixes suggested by @Neon22 have been applied to:
roof_terracotta_EB_mod2.scad. Same Non-commercial license applies

NOTE
DOWLOAD HINGES: http://www.thingiverse.com/thing:1440521

Terracotta shingle roof roof that can have size and shingle tilt via parameters.
Details can be found on my blog:
http://opengeolog.com/tech/2016/03/23/duplo-compatib…a-shingle-roof/

Settings
Size: The size of the entire build is controlled by two variables lenth and width. The spell