SparseHash (0.0) [1:5×1:10]
│ │ 
└─└─[1, 1] [1, 2] [1, 3] [1, 4] [1, 5]         [5, 6] [5, 7] [5, 8] [5, 9] [5, 10]
    2.0    0.0    1.0    2.0    0.0        …   2.0    0.0    1.0    2.0    0.0    

