Abstract: In an embodiment, a fastener includes (a) a main body having a length parallel to a main axis definable through the main body, and a first cross-sectional area transverse to the main axis; and (b) at least a first set of petals carried by the main body, which includes at least one petal. The first set of petals is selectively displaceable (a) about the main axis in a direction transverse to the main axis, separate from or in the absence of axial displacement of the first set of petals in a direction parallel to the main axis, each petal within the first set of petals displaceable between a first position and a second position transverse to the main axis, the first position closer to the main axis than the second position; and (b) axially with respect to the main axis, separate from or in the absence of transverse displacement of the set of petals relative to the main axis.