Idea taken from here: https://www.thingiverse.com/thing:4602658 And here: https://www.thingiverse.com/thing:4616506 Thanks for your designs!!
I use the second design all day long and wanted to scale it down to also print a smaller version for my kids.... ... This failed on me because the upper part got way too thin by just scaling in slicer. I don't know how to use blender, so I designed from scratch in CAD, with 2x8mm cross section of the bars. (Partially added with a diameter 4mm sweep for extra rigidity) Like this I printed versions of my design scaled from 65% to 100% in slicer. Kids are happy with them!