# frozenset error when plotting polytopes: bug?

I am having trouble understanding an error I get, when i try the following:

```
ngon=polytopes.regular_polygon(122).dilation(18.1)
ngon.plot()
```

It says: `KeyError: (frozenset([60]), frozenset([60]))`

The following works:

```
ngon=polytopes.regular_polygon(122).dilation(17.9)
ngon.plot()
```

What is going on? Is this a bug?

i can reproduce this. If it helps you for the moment ngon=polytopes.regular_polygon(122).dilation(181/10) works.