One day, when I was browsing through Pinterest, I came across these funny kinda-puzzly balls handmade in colourful fabric. That looked interesting for me and the next thing I know I'm searching for stitches on how to make my own puzzle balls in crochet.
It's an intriguing crochet project due to the fact that, you find yourself with triangle shapes of crochet pieces, that you have to stitch them together with crochet stitches.
Overall it's nice to make them with colourful yarn or in one color only too. The essencial here is to make them with child-friendly yarn - strong, non-toxic, washable - because this is a child's toy that stimulates them to move towards them, as they exercise their muscles, and as they grow up they get more curious and tosse them around and grabbing them, to a point that they're strong enough to pull them apart and assemble it back together.