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

