There's actually a name for this: loose parts theory, first described by the architect Simon Nicholson in 1971. His point was simple. Children get more inventive with open-ended materials, sand, tile, string, offcuts of wood, than with any single-purpose toy or worksheet an adult designed for them.
Our sessions build on the Reggio Emilia approach, which took that idea even further. Its founder, Loris Malaguzzi, coined the phrase the “hundred languages of children”, the idea that a child can express themselves through clay, thread or paint just as well as through words. A teacher's job, in that view, is to hand over the materials and enough trust, then step back.
That open-endedness is the whole point. A worksheet has one correct answer. A pile of mosaic tile doesn't, so a child has to look, decide, try, and often start over, which is a far richer kind of thinking than following an on-screen tutorial to an answer someone else already decided.