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