If we take this map of Milan of the sixteenth century (whose shape is similar to a decagon) and imagine to identify some couples of sides, we get a bitorus: exhibit of matemilano (in the section "Topology"), realized by Michele Ciribifera and Stefano Bonacci.
foto di Ombretta Locatelli
The image belongs to the sections...:
Exhibition 2004-2005 together with the topology section of matemilano (From the exhibitions of matematita)
The topology section of matemilano shown inside the exhibition Symmetry, playing with mirrors (From the exhibitions of matematita)