flow.size: 8
row.1: 1,0,0,0,0,0,0,2
row.2: 5,0,0,0,6,0,0,0
row.3: 4,0,0,0,0,0,0,0
row.4: 0,0,0,0,0,0,0,0
row.5: 0,0,0,0,0,0,2,6
row.6: 0,0,0,0,5,0,0,1
row.7: 0,3,7,0,0,0,0,0
row.8: 0,4,0,0,0,0,7,3

