krtisfranks wrote:
> Thus, we may want to refine the definition.

The current definition is this:

"x₁ is a set of points/shape (of any number of dimensions) such that
x₁ is connected and there exists a line L such that for any line L' that
is parallel to L, if L' has nonempty intersection with x₁, then there
exists exactly one subinterval (line segment, ray, or line) J of L' such
that J has nonzero (Lebesgue) measure and any subset of L' which nonemptily
intersects x₁ is contained in J. An axially-perpendicular cross-section
of x₁ probably is necessary to specify x₂. See also: slanu,
fru'austumu."