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

