The old "closed polysurface" chestnut again

I have been trying to perfect a couple of things for my own ongoing education and I decided to recreate a flower pot.

I have managed to produce a model that has no naked or non manifold edges.

However it is still an open polysurface, and I cannot work out why.

Pot exercise.3dm (17.1 MB)

Hi,

If you use “showedges” you can see that there are in fact naked edges.

I have attached one that is closed by sweeping.Pot exercise.3dm (8.2 MB)

Thank you for that. Another thing learned. Much appreciated.