In psychological terms, however, it is less easy to follow. To give some kind of a flavour, here are a few of the effects of hyperbolic geometry. Straight lines will appear to be curves. Two lines may be inclined in such a way that if they are extended they will meet, and yet they will not meet, they will appear to curve and yet they will remain straight lines. The Pythagorean theorem, a cornerstone of Euclidean geometry, is not true.
Scale models are impossible, as the size changes, so do the angles.
The larger the area of a triangle, the smaller the sum of its angles. And if two triangles have the same angle sum, they have the same area. There is an upper limit on the area of a triangle. The best way to understand hyperbolic geometry is to see it illustrated . It took a while for hyperbolic geometry to be accepted.