Steiner surface
The
Steiner surfaces are self-intersecting embeddings of the real
projective plane into three-dimensional space. More particularly, they are linear projections of a six-dimensional embedding called the Veronese surface, which is the image of an ordinary 2-sphere centered at the origin under the map
f(
x,
y,
z) = (
x2,
y2,
z2,
yz,
xz,
xy). There are ten different types, including the
Roman surface and
cross-cap.
