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