Legos represent static building and K'Nex a plastic version of the old open-frame erector sets without the need for nuts and bolts.

The Fischer toys, on the other hand, are closely geared to real construction modules. Beginning at an early age the child can build simple vehicles. All the parts used then will still be applicable when they are in high school creating real assemblies including both humanoid and industrial robotics.

They therefore give an opportunity for a parent to build a sophisticated collection of building materials that can grow all the way from simple to modelling real factory assembly lines, as Volkswagon did for one of theirs using $300,000 worth of FischerTechnik parts.

The expense of a useful assemblage can thus be spread over a child's play lifetime, making a highly useful assemblage of blocks affordable in the long run.