Hello, I'm trying to solve a problem that works on an extruded periodic interval mesh on an extruded circle mesh. I am getting the following error: Traceback (most recent call last): File "extruded_circle_helmholtz.py", line 57, in <module> bcs = [DirichletBC(W[0], Expression(("0.", "0.")), "bottom"), File "/home/jemma/src/firedrake/firedrake/bcs.py", line 56, in __init__ self.function_arg = g File "/home/jemma/src/firedrake/firedrake/bcs.py", line 95, in function_arg g = function.Function(self._function_space).interpolate(g) File "/home/jemma/src/firedrake/firedrake/function.py", line 182, in interpolate % (sum(dims), np.prod(expression.value_shape(), dtype=int))) RuntimeError: Expression of length 3 required, got length 2 The problem appears to be that the mesh coordinates have 3 components whereas the extruded interval mesh coordinates only have 2. Any idea how to fix? My code is here: https://gist.github.com/anonymous/dff509883518ef0f5f2d Thanks! Jemma