It is the set of points, in 3-dimensional space, defined by the intersection of two planes which define faces of the shape.
yes
It is possible.
Since the question is unfinished, I'll assume the most obvious completion: "planes." Yes, a triangular pyramid is composed of 4 non-co-planar points which form 4 intersecting planes.
A plane midway between the two given planes and parallel to them.
Two are enough, if not coplanar.
It is the set of points, in 3-dimensional space, defined by the intersection of two planes which define faces of the shape.
Any three given points can be joined by a common plane, and any two given points can be joined by a common line and an infinite number of common planes.
skew
yes
Noncoplanar is a term in geometry referring two or more figures, lines, or points that do not all lie in the same plane.
skew lines
It is possible.
Since the question is unfinished, I'll assume the most obvious completion: "planes." Yes, a triangular pyramid is composed of 4 non-co-planar points which form 4 intersecting planes.
If there are two unique, non-parallel planes in space, they will intersect, and their intersection will be a line.
A plane midway between the two given planes and parallel to them.
If they are straight lines, then they define a plane in which both lines lie.