Erector-like sets have a tremendous educational value. They help to gain spatial understanding and to learn by experimenting about strength and stability of constructions. Many of the people we know with a mechanical mind set, able to design and construct objects and machines have learned this by play with an erector set.
It is obvious that having the chance to play with Meccano in one's youth helps a lot in solving technical problems when older. A drawback of the Meccano or Lego construction parts is the scale. What can be constructed with it is never more then a model of something that is normally larger in scale. If what can be constructed has a size and a sturdiness, in which it can perform a realistic function as a hut or a cart, it may help to develop a childs ability to take initiative. This would also integrate playing with construction materials in other games in which a child is involved with mates.
Thin, straight sticks are interconnected when they are stuck into holes drilled into blocks and fastened with wedges of a special design. These provide a sturdy connection although they can be placed and removed by hand. Disks can turn around the sticks. Cart and cots in any shape can so be made by a kid.
These sticks can be interconnected either flexible, or free to rotate or stiff and sturdy with construction elements that children can easily handle. Such construction elements can be blocks of wood in which sticks can be fastened with wedges or rubber strips for flexible joints. Bushes that can act as bearings for parts that turn can also be attached to such flexible rubber strips or blocks. Fastening of the parts is done in a way it can be done by children without tools. Cart and cots in any shape can so be made by a kid.