Commissure Ocular Caudal

*Coffin Spike* is one of the simple and rare problems from topology, solved thanks to the concept of *spike*.

*Spike* (pin, snag, hairpin) is a homological object in group algebra, generalizing the concept of a simple element in a ring (group unit). This is an "interpretation of the concept regarding the nodal rotation of the trochoid" in space. Two curves on the same plane can be drawn only in such a way that they are not self-intersecting and limit the same area. But on a two-dimensional sphere these restrictions disappear: here you can lay two such curves very close to each other until they cover each other. With further rotation around the sphere, pairs of points (one on each curve) will pass through each other (*get hooked*) and find themselves connected by a connecting segment. Thus, if two intersecting curves are first twisted around each other using a 3D rotation (rotation on a sphere),