Pb1
100, 100; 100, 300; 300, 300; 300, 100; 
0, 1; 1, 2; 2, 3; 3, 0; 
Pb2
100, 100; 100, 300; 300, 300; 300, 100; 500, 100; 500, 300; 
0, 1; 1, 2; 2, 3; 3, 0; 0, 2; 3, 4; 4, 5; 5, 2; 
Pb3
100, 100; 100, 300; 300, 300; 300, 100; 500, 200; 
0, 1; 1, 2; 2, 3; 3, 0; 1, 3; 3, 4; 4, 2;