The first format of the loop shape data, interior angles are used to specify the shape. If there are n nodes, only (n-3) interior angles are needed to determine the shape. Interior angles are the essential elements to determine the shape, withous over-define the size like the node position data. Some reasoning is needed to find the rest interior angles and calcualte the node positions.
However, a new format of robot positions is still used in "loop-data2".
