In mathematics, a helix is a 3-dimensional curve. The equation of a helix in cylindrical coordinates is:
... (USSR) Cheka (1917-1922) Gosudarstvennoye Politicseskoye Upravleniye[?] (GPU, 1922-1923) Obyedinennoye Gosudarstvennoye Politicheskoye Upravleniye[?] (OGPU, ...