A pseudosphere
In the library Bolyai-Teleki, in Târgu Mureş (Romania), there's a model of pseudosphere, where we can see that, in hyperbolic geometry, the sum of the internal angles of a triangle is smaller than 180°. On the back, we can also see that there are more than one line that pass through a point and are parallel to a given line.
© matematita
The image belongs to the sections...:
Hyperbolic geometry (Other geometries)
