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