8formájú

8formájú, literally eight-shaped in Hungarian, refers to objects or forms whose outline resembles the numeral eight or comprises two loops that meet. The term is used in mathematics, design, and engineering to describe curves and structures with a double-loop silhouette.

In mathematics, the most familiar eight-shaped curve is the lemniscate, a class of plane curves resembling a sideways eight. The Bernoulli lemniscate is the canonical example, often described in polar coordinates by r^2 = a^2 cos 2θ, which is equivalent to the Cartesian equation (x^2 + y^2)^2 = a^2 (x^2 − y^2). It has a self-intersection at the origin. Another variant is the Gerono lemniscate, a simple eight-shaped curve given parametrically by x = cos t, y = sin t cos t, used as a teaching example in the study of plane curves.

In design and culture, eight-shaped motifs appear in decorative borders, ribbons, and logos, where the form can symbolize continuity, balance, or duality. The infinity symbol is a stylized eight lying on its side, and in architectural and engineering contexts double-loop forms may be employed for both aesthetic and functional reasons, such as creating related flow or tension in a structure.

See also lemniscate; infinity symbol; figure-eight knot.