Minimal Networks - Steiner's Problem 
Minimal network between three points
Choose three cities in the map by moving the points \(A, B, C\) to the desired location.
(In order to work, the points \(A,B,C\) should be chosen clockwise.)
The minimal (shortest) network of roads that links those three cities is displayed automatically.
In order to understand why this is the configuration of the shortest network for the three cities, you may consult Fermat's problem and the construction obtained by Torricelli's method or by Simpson's method.
