3
[1: 0.0 1.0 2.0]
[1: 0.0 0.0 0.0]
2
[1:[1: 1 2] [1: 2 3] ]
4
[1:[1: 1 1] 
   [1: 1 2]
   [1: 2 2]
   [1: 3 2] ]
1
[1: [1: 3 1] ]
[1: 2.0 ]
