Copies of the project description, in Postscript and PDF.
A copy of an optimal (Euler) circuit, in PDF.
Essentially, the edges marked (1) give an optimal Eulerization. But the two edges marked (2) must be added
in order to avoid going down a one-way street the wrong way. Without them, the vertices on both ends have
more streets coming in (or out!) than out (or in!)