A form of

symmetry in which parts of an object appear the

same as
other parts, such that if you

rotate the object by some amount, it
looks like the same object. For example, this figure has two-fold rotational symmetry:

oooo....
oooo....
oooo....
....oooo
....oooo
....oooo

By rotating the

figure through 180 degrees, what you get looks like what you
started with.

Objects with three-fold rotational symmetry, such as a triskelion,
can be rotated in increments of 120 degrees, and appear the same. In general,
if an object appears the same n times during a 360 degree rotation, it is said to have
M-fold symmetry, where M = 360/n.

Note that figures with rotational symmetry do not necessarily exhibit reflection symmetry, although there exist figures with
reflection symmetry that also show rotational symmetry. One example is a star shape.