Work in progress - how to interpret polylines approximating curves on a surface

Every wireframe model of a smooth surface is considered as a simple but very rough approximation. However it contains rich information. In this paper a piece of an approximated tangent plane, a tangent cell, is defined from a wireframe model in order to introduce students to an approximation of connection by making a tree of tangent cells. When this tree is put on a plane, parallel transport of a vector is equal to its parallel shift on the plane in usual meaning.