IC 418 IC 418 IC 418, also known as Spirograph Nebula, is a planetary nebula in the Milky Way Galaxy. The name derives from the intricate pattern of the nebula, which resembles a pattern which can be created using the Spirograph, a toy that produces geometric patterns (specifically, hypotrochoids and epitrochoids) on paper. Only a few million years ago, IC 418 was probably a common red giant star. Since running out of nuclear fuel, though, the outer envelope has begun expanding outward leaving a hot remnant core destined to become a white dwarf star. IC 418 lies about 3600 light-years away and
Geometric function theory Geometric function theory Geometric function theory is the study of geometric properties of analytic functions. A fundamental result in the theory is the Riemann mapping theorem. The following are some of the most important topics in geometric function theory: A conformal map is a function which preserves angles locally. In the most common case the function has a domain and range in the complex plane. More formally, a map, is called conformal (or angle-preserving) at a point formula_3 if it preserves oriented angles between curves through formula_3 with respect to their orientation (i.e., not just the magnitude of the angle).