My three year old loves playing with a marble race puzzle inside a plastic ball, called a Perplexus. He can play with it for hours on end.
I can relate to this! For my 22nd birthday my parents to me one of these because I constantly tried to solve my cousins. Trying to solve the whole thing is easily one of the most addictive yet infuriating non-digital toys I have ever played with. Still who’s using it more than a year later!