Thanks for your kind help .

I want to rewrite my problem as flows:

```
from fenics import *
from mshr import *
mesh1 = UnitSquareMesh(2, 2)
domain = Rectangle(Point(0, 0), Point(1, 1))
mesh2 = generate_mesh(domain, 30)
```

We can get mesh1 and mesh2 by running this code .How to get the (left) boundary points coordinate ?

This may be a simple problem in this example, but if the mesh boundary is moved using ALE.move(), what can i do to get the new boundary points coordinate ?

the code is :

```
from dolfin import *
from mshr import *
import numpy as np
import matplotlib.pyplot as plt
W = 2.0
H = 1.0
domain = Rectangle(Point(0, 0), Point(W, H))
mesh = generate_mesh(domain, 20)
class Right(SubDomain):
def __init__(self):
SubDomain.__init__(self)
def inside(self, x, on_boundary):
return on_boundary and near(x[0], W)
right = Right()
#bmesh = BoundaryMesh(mesh, "exterior", True)
bmf = MeshFunction("size_t", mesh, mesh.topology().dim() - 1, 0)
bmf.set_all(0)
right.mark(bmf, 1)
V= VectorFunctionSpace(mesh, "CG", 1)
x = SpatialCoordinate(mesh)
u = Function(V)
#boundary displacement
bcs = project(as_vector((0.1*x[1]*(1 - x[1]), 0)), V)
#bcs = Expression(("0.05*sin(4*(pi/L)*x[1])", "0.0"), L=1, degree=1)
bc = DirichletBC(V, bcs, bmf, 1)
bc.apply(u.vector())
plot(mesh)
plt.show()
ALE.move(mesh, u)
plot(mesh)
plt.show()
```

How to get the new mesh (right) boundary points coordinate ?