One is the dual turn head method, where two rotational coordinates directly control the direction of the tool axis;

The two are the hanging rotating head method, with two coordinate axes at the top of the cutter, but the rotation axis is not perpendicular to the linear axis;

Three are dual turntable modes, where two rotation coordinates directly control spatial rotation;

Four are sagging workbenches, with two axes on the workbench, but the rotation axis is not perpendicular to that axis;

Five is a swing starting from one rotation, with two rotation coordinates on one tool and one on the workpiece.