When poles to bedding surfaces from a folded rock sequence are plotted on a lower-hemisphere, equal-area stereographic projection, poles from a cylindrically folded surface (one that can be generated by translating a single line, the fold axis, through space) all fall along a single great circle, whose own pole represents the orientation of the fold axis (this method is known as the beta or pi-diagram technique for determining fold axis orientation); a scattered, non-great-circle distribution instead indicates non-cylindrical folding.