Meccano again

To make Lego stronger and more rigid they recommend adding more bricks.  You can also use glue but then you can't modify the machine.  Meccano, be it plastic or metal, is held together with screws. This holds the parts together more securely but you can still modify it if you wish to. We can build robots with meccano too.  The pain system would have to be modified of course. (Blog of 31 March 2016)