This is a fascinating subject. I stumbled into it (without knowing of Chebyshev) while playing with a "lego walker" back in 2018. Even did a couple of blog posts [0,1] (in danish, and mostly for my own benefit) exploring the geometry.
Only recently did I learn of the Chebyshev linkage, which has a "lambda variant" [2] is basically what I was looking for in the walker (except it needs to be upside down, as in Chebyshevs own "walker" or "plantigrade" [3]).
For anyone wondering about the domain name: Week 42 is the "autumn break" in Denmark: kids are home from school, you are still filled with travel from your summer holiday, weather is typically ok -- so in short, it is the perfect time do work on fun projects with the kids.
As an American, it always surprises me that people in other countries actually use week numbers in common use. I first ran into this when I was planning a trip in Norway and read something about how the train I had hoped to take would be under repairs in, I think, week 31.
Only recently did I learn of the Chebyshev linkage, which has a "lambda variant" [2] is basically what I was looking for in the walker (except it needs to be upside down, as in Chebyshevs own "walker" or "plantigrade" [3]).
[0]: https://hack42.dk/2018/04/lego-walker/ [1]: https://hack42.dk/2018/04/geogebra-og-gaamaskiner/ [2]: https://en.wikipedia.org/wiki/Chebyshev_lambda_linkage [3]: https://en.wikipedia.org/wiki/File:Tchebyshevs_plantigrade_m...
(Edit: formatting)