flow.size: 8
row.1: 0,2,4,0,0,0,0,1
row.2: 0,0,0,0,0,0,0,0
row.3: 2,7,9,0,9,0,0,0
row.4: 3,8,0,0,0,0,0,0
row.5: 0,0,7,0,0,6,0,0
row.6: 0,0,8,0,0,1,0,0
row.7: 0,0,3,6,0,4,0,0
row.8: 5,0,0,5,0,0,0,0












