1. The arms were previously missed due to M82's high disk surface brightness, the nearly edge-on view of this galaxy (~80°), and obscuration by a complex network of dusty filaments in its optical images.

2. Two novel techniques are proposed to design such surfaces: a technique for obtaining a freeform variation of a rigid-foldable and Bidirectionally flat-foldable disk surface, which is a hybrid of generalized Miura-ori and eggbox patterns, and a technique to generalize the geometry of cylindrical surface using Bidirectionally flat-foldable planar