Blocks" that can be horizontally assembled into a large medieval castle, DUPLO sizeYour choice:The source code is no different from its "parent", i.e. thing http://www.thingiverse.com/thing:31284 that uses LEGO size for the STLs.I just generated DUPLO size and proportions instead of Lego size and proportions, for folks who don't want to learn OpenScad.Therefore this "derivative" is just a Duplo "subdirectory" that includes a subset. Please go and read the rest in the parent.DisclaimerI didn't print any of these models. However, I did print similar structures. See a picture in http://www.thingiverse.com/thing:2106Expected problemsfloors over DUPLO-base (nibbles underneath). Plastic may bond sideways and in knots: Try to print as cold as possible (and tighten the extruder). In addition - as soon as you get irregular surfaces in large horizontal fully filled roof layers - you could turn off the fan, so that the nozzle won't get stuck. The visible top layer of a base plate should come out ok if you use enough fill and the bottom will be ok iff you print it slowly and nozzle real close to print bed.Random filament feeding problem after many hours of printing.SuggestionsI suggest to print these models as speedy as possible, unless your printer doesn't mind 24hour prints.However, the first layer must printed very very slowly. Try with the small calibration block first.FitFit of DUPLO-compatible connectors is rather loose in order to compensate for sloppy quality and thicker layers.If your printer is reliable and you don't mind waiting a day, try 0.2 or 0.25 layers with a rather dense fill for good results. In any case, for quality, you should not use these STLs, but rather adjust the parameters in the OpenScad file (see the "parent", http://www.thingiverse.com/thing:31284 as well as my OpenScad library: http://www.thingiverse.com/thing:2106 which does the work behind. These Duplo models are just lists of function calls...