# Unexpected intersection between parallel polygons.

The `intersection`

function returns a non-empty intersection for two polygons that are separated in space.

The following is a reproducible example:

```
# Define parallel polygons.
a = Polyhedron([[0, -1, 1], [1, -1, 1], [1, 1, -1]])
b = Polyhedron([[0.0, -0.5, 1.5], [1.0, -0.5, 1.5], [1.0, 1.5, -0.5]])
# Intersection.
c = a.intersection(b)
# c ->
# `A 2-dimensional polyhedron in RDF^3 defined as the convex hull of 3
# vertices (use the .plot() method to plot)`
a.plot(fill='green') + b.plot(fill='red') + c.plot(fill='orange')
```

Same here (Sage 9.2.beta7).

`c`

has the same vertices as`b`

:Curiouser and curiouser :

I'm tempted to say it's a bug, but I knows

silchabout polyhedra...Note: also asked, and answered, on the sage-devel mailing list:

Now tracked at