"DJ" (music) control for toddlers - colloquially referred to as "the buttons" in our family, they've brought substantial peace to our household & they've helped our kids improve at negotiation/compromise/etc.
I read your article - followed the intro quite closely and then looked for the solution and it was 'the buttons' followed by a bunch of technical stuff that kind of made me loose focus. So in the end I don't know exactly what 'the buttons' is hahah. Reminds me of the Hudsucker Proxy. 'You know, for kids!'
Details here: https://dantonio.info/projects/the-buttons/