Difficulty is varied across the various levels mainly by changing the following task characteristics:
- the figural complexity of the objects
- the direction and angle of rotation
- the object’s positional complexity
- the complexity of the coordinate system implied by the cameras or rotation rods.
The training program uses objects of various different types (e.g. cartoons, buildings). The aim of using a wide range of practice material is to improve the client’s motivation to train and to ensure that the cognitive skill that is developed can be generalized effectively.