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