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