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

