English: Regular icosahedron reduced by 1 edge contraction: merging 1 edge into 1 vertex. Here, this contraction:
● Removes:
  • 1 vertex,
  • 3 edges and 2 adjacent faces incident with this vertex.
● Makes 2 adjacent edges collinear, and places 6 faces in a folded regular hexagon, i.e. in 2 adjacent congruent triamonds.
(A triamond is made of 3 coplanar adjacent congruent equilateral triangles.)
● Distorts the circumscribed sphere of the original vertices.