Apertured article, insertion article and associated systems

An apertured article comprising:

• a body that defines an aperture passing through from a first side of the body to a second side of the body, wherein:
• the aperture comprises an outer periphery coinciding with a first reference circle with a first radius and an inner periphery coinciding with a second reference circle with a second radius that is less than the first radius,
• the inner periphery defines a plurality of inner peripheral surfaces forming elongated arcs that are concentric with the first reference circle and the second reference circle, and
• the outer periphery defines a plurality of outer peripheral surfaces forming elongated arcs that are concentric with the first reference circle and the second reference circle.

An insertion article comprising:

• an elongated body that has a uniform, transverse cross-sectional area along its length, wherein:
• the transverse cross-sectional area has an outer perimeter including an outer periphery coinciding with a first reference circle with a first radius and an inner periphery coinciding with a second reference circle with a second radius that is less than the first radius;
• the inner periphery defines a plurality of inner peripheral surfaces forming elongated arcs that are concentric with the first reference circle and the second reference circle;
• and
• the outer periphery defines a plurality of outer peripheral surfaces forming elongated arcs that are concentric with the first reference circle and the second reference circle.