Hi gang ! Attached some basic POC code. Its purpose is to see how the spiral moves, not to be the end product. I've printed pieces and tried to "guess"/"feel" the motion. The current code is the 1st attempt. The spiral is free to move translation-wise but should rotate continuously. It is to touch two of the edge posts at all times. As you see, my current guess is its centre moves along a triangle path. It doesn't quite seem to fit. Possibly the code can be made more "elegant" allowing for a more complex translation path of the spiral. It is not important to get a mathematical formula, a coding hack is fine. The question I am trying to get: can it be done? Can the spiral constantly touch at least two posts while rotating, without any discontinuity/jumps? This is planned to be part of an artistic moving sculpture, largish.... Msquare

Ok, yes totally impossible, but then I relax/change the constraints - it must touch one edgepost at all times, and touch two edgposts when possible, making as smooth transition as possible. M² man. 2. feb. 2026, 13.33 skrev Michael Möller <private2michael@gmail.com>: > Hi gang ! > > Attached some basic POC code. Its purpose is to see how the spiral moves, > not to be the end product. I've printed pieces and tried to "guess"/"feel" > the motion. The current code is the 1st attempt. > > The spiral is free to move translation-wise but should rotate > continuously. It is to touch two of the edge posts at all times. As you > see, my current guess is its centre moves along a triangle path. > > It doesn't quite seem to fit. Possibly the code can be made more "elegant" > allowing for a more complex translation path of the spiral. It is not > important to get a mathematical formula, a coding hack is fine. The > question I am trying to get: can it be done? Can the spiral constantly > touch at least two posts while rotating, without any discontinuity/jumps? > > This is planned to be part of an artistic moving sculpture, largish.... > > Msquare > > >

Looks a bit like a scroll compressor, but why the triangular motion? Maybe some ideas here: https://en.wikipedia.org/wiki/Scroll_compressor