There is an array of orthogonal segments; each segment is represented by points P1, P2; segments are connected to each other, i.e. points P1 and P2 intersect with other points P1 and P2 of other segments. It turns out a picture like the following 
Accordingly, the user can drag these segments and points of corners and joints. The segment point that ends in red is considered fixed; it can only move if the user moves the red square.
As in such cases, the limitations of moving points are described as well as the connections between segments so that, for example, moving the lower right corner moves the segments connected with it.
