A pattern of five (sometimes more) vent-like holes found as a trademark design element on mecha designs by Izubuchi Yutaka.
Usually arranged in a trapezoidal pattern of three above and two below. Often found in pairs along the sides of mecha head units, or on the shoulder pauldrons. The AV-98 Ingram features them on both its head (3+2, rotated) and shoulder (3+4) units.
