yes
Yes it can
No, not normally
true!! apex.
false
No. See, for example, the top image in the attached link.
Yes.
Yes, it can.
yes
Yes. A regular tessellation can be created from either an equilateral triangle, a square, or a hexagon.
No, a tessellation cannot be created using only regular pentagons. This is because regular pentagons do not fit together to fill a plane without leaving gaps or overlapping. The internal angles of regular pentagons (108 degrees) do not allow for combinations that sum to 360 degrees around a point, which is necessary for a tessellation. Other shapes, like triangles, squares, or hexagons, can tessellate because their angles allow for such arrangements.
M.C. Escher (dutch)
Yes it can
Venus Equilateral - collection - was created in 1947.
No, not normally
Sporting Triangles was created in 1987.
Pittsburgh Triangles was created in 1974.
Dayton Triangles was created in 1913.