Even today, what makes Lego superior to their competitors (to the extent that e.g. eBay sellers take pains to guarantee their packs of random bricks contains nothing but genuine Lego...) is that the pieces are manufactured with surprising precision and have a <i>lot</i> of little details that most people aren&#x27;t even aware of.<p>E.g. wonder why Lego Technic sets and similar uses a mix of black and grey connecting studs instead of just sticking to one? The grey ones will rotate more easily, so depending on whether you want to lock something in place or enable it to rotate more freely (e.g. wheel, rotor) you&#x27;ll use different ones. If you look at them up close, this is achieved by tiny little ridges (fractions of a mm tall and fractions of a mm wide) on the black ones. There&#x27;s also a slit in he black ones, not sure what if anything that makes a difference to.<p>Most non-Lego bricks lack a lot of those details, and that makes them less flexible to use.