Linear motions of violet slider along X and Y axes are controlled by orange and green driving pulleys.
The black timing belt is fixed to the violet slider.
When pink and green pulleys rotate in opposite directions at the same velocity, the object moves along Y axis.
When pink and green pulleys rotate in the same direction at the same velocity, the object moves along X axis.
When only one driving pulley rotates, the violet object moves obliquely.
The green line is trajectory of a point on the object.
The mechanism can be used for 3D printers.
Disadvantage: the violet slider mass is large.