Is their a Hierarchy of Constructive Geometry? In constructive geometry, there is a tradition that the purest constructions are those constructible with compass and straight edge alone, specifically a compass that collapses when lifted and an unmarked straight edge. Under these rules, there are 3 famous problems that are known to be impossible: Angle Trisection Doubling the cube, which requires taking a cube root,, which I understand is somewhat analogous to angle trisection. Squaring the circle, which requires constructing a transcendental length. And there is the concept of constructible polygons, regular n-gons that can be constructed with compass and straight edge alone. However, compass and straight edge aren't the only tools in the more open minded constructive geometer's toolkit. Some traditional examples include an angle trisector and neusis constructions, the latter which involves the use of a marked ruler and sliding it over a surface. Neusis can be used to trisect arbitrary angles, but an angle trisector on it's own can't do everything a neusis construction can, so in a sense, an angle trisector is strictly weaker than neusis. But are their tools strictly stronger than compass and straight edge and strictly weaker than angle trisector or strictly stronger than angle trisector, but strictly weaker than neusis? Are their tools that can do some of what neusis can that angle trisector can't while not being able to do everything angle trisector can? Where do tools for constructing ellipses, parabolas, and hyperbolas fit into the hierarchy? What about tools for generating hypotrochoids and epitrochoids? Is Origami greater than, less than, or equal to neusis? A regular Heptagon is the smallest regular n-gon not constructible with compass and straightedge, but is constructible with angle trisector. A regular hendecagon is the smallest regular n-gon not constructible with angle trisector, but is constructible with neusis. A regular 23-gon is the smallest regular n-gon not constructible with neusis. What is the simplest tool that can construct a regular 23-gon and what is the smallest regular n-gon this tool can't construct?