Part One: The VRML Source Code for a triangulated octagon (fatsign.wrl)

Here is what you would normally see exported from a 3D modeling package:

#VRML V2.0 utf8
#Thin-faced tutorial file
Transform {
  children [
    Shape {
      appearance Appearance {
        material Material {
          emissiveColor 1 0 0
        }
      }
      geometry IndexedFaceSet {
        coord Coordinate {
          point [
                  -0.5 1.5 0,
                  -1.5 0.5 0,
                  -1.5 -0.5 0,
                  -0.5 -1.5 0,
                  0.5 -1.5 0,
                  1.5 -0.5 0,
                  1.5 0.5 0,
                  0.5 1.5 0,
          ]
        }
        coordIndex [ 0, 1, 2, -1,
                     0, 2, 3, -1,
                     0, 3, 4, -1,
                     0, 4, 5, -1,
                     0, 5, 6, -1,
                     0, 6, 7, -1,
        ]
      }
    }
  ]
}

Part Two: The VRML Source Code for a single-faced octagon (thinsign.wrl)

#VRML Draft #3 V2.0 utf8
#Thin-faced tutorial file
Transform {
  children [
    Shape {
      appearance Appearance {
        material Material {
          emissiveColor 1 0 0
        }
      }
      geometry IndexedFaceSet {
        coord Coordinate {
          point [
                  -0.5 1.5 0,
                  -1.5 0.5 0,
                  -1.5 -0.5 0,
                  -0.5 -1.5 0,
                  0.5 -1.5 0,
                  1.5 -0.5 0,
                  1.5 0.5 0,
                  0.5 1.5 0,
          ]
        }
        coordIndex [ 0, 1, 2, 3, 4, 5, 6, 7, -1, ]
      }
    }
  ]
}