How to generate meshes for multiple subdomains so that its normal vector points from one area to another? Can the processing methods in the tutorial solve this problem?

The example in the tutorial ：

geometry = SplineGeometry()

pnts = [ (0,0), (1,0), (1,1), (0,1), (2,0), (2,1)]

pnums = [geometry.AppendPoint(*p) for p in pnts]

lines = [ (pnums[0],pnums[1],1,1,0), (pnums[1],pnums[2],2,1,2),

(pnums[2],pnums[3],3,1,0), (pnums[3],pnums[0],4,1,0), (pnums[1], pnums[4],5,2,0),

(pnums[4],pnums[5],6,2,0), (pnums[5],pnums[2],7,2,0)]

for p1,p2,bc,left,right in lines:

geometry.Append( [“line”, p1, p2], bc=bc, leftdomain=left, rightdomain=right)

return

mesh = Mesh(twoDomain().GenerateMesh (maxh=0.1))

Draw(mesh)