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












