The group of symmetries of an equilateral triangle, known
as *D*_{3}, is generated by two operations:
counter-clockwise rotation by a one-third turn (denoted *a*)
and reflection across a horizontal axis (denoted *b*).

Clicking each button performs the indicated operation. The aggregate
transformation is shown in “standard form” above each
triangle. The equation below the diagrams indicates the algebraic
operation that transforms the left-hand diagram into the right.
(Remember that function composition is read from right to left. For
example, the product *ab* is the transformation obtained by
reflecting first, then rotating.)