A vertical line
A sphere
a quadrilateral
A line. Or a circle
A cylinder.
Irregular shape is the term given to an object which has 1 flat side, 1 curved side, no corners but has curved edges.
Any curved shape such as a circle, an ellipse, an oval, a wriggly line - as long as it does not have any corners.
Spherical
sphere
a circle
according to me its octagon
A very common shape: the triangle. It is a flat plane that has only 1 face and always has 3 vertices or corners.