text: from decomposition import Edge, demo
  
  edges1 = [Edge(0, 100, 0, 250),
            Edge(0, 100, 50, 100),
            Edge(50, 100, 50, 0),
            Edge(0, 250, 100, 250),
            Edge(100, 250, 100, 200),
            Edge(50, 0, 150, 0),
            Edge(100, 200, 150, 200),
            Edge(150, 200, 150, 0),
            ]
  demo(edges1)
  
  edges2 = [Edge(0, 0, 0, 50),
            Edge(0, 50, 50, 50),
            Edge(50, 50, 50, 100),
            Edge(0, 100, 50, 100),
            Edge(0, 100, 0, 125),
            Edge(0, 125, 25, 125),
            Edge(25, 125, 25, 150),
            Edge(0, 150, 25, 150),
            Edge(0, 150, 0, 175),
            Edge(0, 175, 75, 175),
            Edge(75, 175, 75, 200),
            Edge(25, 200, 75, 200),
            Edge(25, 200, 25, 225),
            Edge(25, 225, 100, 225),
            Edge(100, 175, 100, 225),
            Edge(100, 175, 125, 175),
            Edge(125, 75, 125, 175),
            Edge(75, 75, 125, 75),
            Edge(75, 0, 75, 75),
            Edge(0, 0, 75, 0),
            ]
  demo(edges2)
  
  edges3 = [Edge(0, 0, 0, 150),
            Edge(0, 150, 150, 150),
            Edge(150, 100, 150, 150),
            Edge(50, 100, 150, 100),
            Edge(50, 50, 50, 100),
            Edge(50, 50, 150, 50),
            Edge(150, 0, 150, 50),
            Edge(0, 0, 150, 0),
            ]
  demo(edges3)