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