As, when using 2D DGEs, dragging provides learners with an interactive way
of validating their own constructions, much effort in task design has focused
on encouraging learner conjecturing and on developing sequences of tasks that
move pupils from conjectures to proofs (for examples, see Laborde et al. 2006).
One interesting form of task is akin to a ‘black box’ (see Laborde 1998) by which
learners are provided with a DGE figure for which they do not know the construction.
The task is to construct a figure which has identical behaviour when dragged.