Hello everyone... I am trying to find the right terminology and/or pictures of something that can be described like this: "the input jacks are fixed in position with respect to the body, and the body is designed so that when the body is expanded or contracted, the jacks move with it in proportion. For example, the distance between the jacks increases or decreases in proportion to the expansion or contraction of the body" I envision something that looks like this: /`\/`\/`\/`\/`\/`\/`\/`\/`\/`\/`\/`\/`… The input jacks rest on the flat peaks. And when the body is expanded or contracted, the inputs move in proportion. the height of the input jacks shouldn't rise/fall with compression/expansion - while still staying in proportion to the body none the less. Is there a name for something in engineering that does this? Or maybe more importantly, can anyone find any images (maybe on google images) that show what is described above? Im having a very hard time with this. Thanks everyone!!!