tandem bicycle.
Parallelogram
an angle
a semi-circle
A quadrilateral
a digon ']* * * * *There cannot be such a shape.
a heptigon
A hendecagon or endecagon.
what do we call in the two sided fastener
you call a seven sided shape a heptagon.
triangle isosceles triangle
An 11 sided shape is an Eptogon
a 9 sided shape is a nonagon