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












