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

