Is there any way to connect “sideways” to an axle? There are some pieces whose middle part is shaped like a Technic axle, but that have elements on both ends that make it impossible to insert them into a normal axle or Technic hole:



This makes me wonder whether the axle shape here actually allows for a connection or was only chosen for stability, production reasons, or similar.
With other words, is there any piece (or combination of pieces) that connects a Technic axle “sideways”, i.e., without going over the ends?
I don't think there are any pieces LEGO intends for you to attach to the side of these axle shaped pieces. However, I'm pretty sure you could attach piece 32172 to some extent (assuming the piece being attached to is actually the right size for an axle):



It probably would not connect very well, only the clips on the sides of the socket would hold it, so it would probably slide easily, or pop of with little effort, but it could be attached.