平面性判定：完全二部グラフ K3,3 の例

Graph :
 0 0 0 1 1 1
 0 0 0 1 1 1
 0 0 0 1 1 1
 1 1 1 0 0 0
 1 1 1 0 0 0
 1 1 1 0 0 0

0-th block with vertices  0 1 2 3 4 5 

 0 0 0 1 1 1
 0 0 0 1 1 1
 0 0 0 1 1 1
 1 1 1 0 0 0
 1 1 1 0 0 0
 1 1 1 0 0 0

Current picture :
 0 0 0 1 1 0
 0 0 0 1 1 0
 0 0 0 0 0 0
 1 1 0 0 0 0
 1 1 0 0 0 0
 0 0 0 0 0 0

Regions :
R[0] : 0 3 1 4 0 
R[1] : 0 4 1 3 0 

Extending path in R[0] :
0 5 1 

Current picture :
 0 0 0 1 1 1
 0 0 0 1 1 1
 0 0 0 0 0 0
 1 1 0 0 0 0
 1 1 0 0 0 0
 1 1 0 0 0 0

Regions :
R[0] : 0 5 1 4 0 
R[1] : 0 4 1 3 0 
R[2] : 0 3 1 5 0 

G  is not planar.