Leonardo da Vinci inspired self supporting bridge

I designed this bridge puzzle for the Maker Faire Vienna in April. It is inspired by the sketches of Leonardo da Vinci and holds together without any glue, nails or screws thanks to interlocking pieces in the easy version and only due to friction between the parts in the hard version.

For both versions I uploaded a file containing 7 sets of pieces (bridge_xxxx_7x.dxf) which is enough for building a reasonable sized bridge. If you want a bigger one you can cut more pieces using the files for o