I have a part I am designing for a class to be 3D printed as an assembly. My parts are complete but I have been having a hard time finding/applying the correct mates to allow for the movement of the parts as needed. My part consists two ends. One end has a sphere attached to a neck, the other end has 4 legs with a 1/4 sphere cut out of each. This is to accept the sphere from the other end when two or more parts are assembled. When two or more parts are attached movement of one part should be restricted to in between the legs of the part it is attached to. I am having a heck of a time creating mates to constrain the movement to allow for the neck the sphere is attached to, to move only between the legs. Any help would be greatly appreciated. Thank you in advance. Please take it easy on me I am fairly new to SolidWorks. I have attached the parts in question.