On a plane, two rods cross each other (without friction) and rotate around intersection point. This basic form can be transformed as follows.
1) Body of mass m is attached to both ends of one rod. Body of mass 2m is attached to both ends of the other rod. Mass of rods is assumed to be zero.
2) Body of mass m is attached to each of four ends of two rods. Length of one rod is a, and length of the other is 2a. Mass of rods is assumed to be zero.
Centrifugal force and tension acting on rods are real forces, not fictitious. From any frame.
