Weasly Twins - inventions

[Carla (Ball) McCulley]

No: HPFGUIDX 161942

In the fourth and fifth books a lot is said about the various
inventions of the Weasly twins.  I have a feeling that their
gift for invention will come into play in a big way in the final
battle.  JKR gives so many details about their experiments and
creations (extendable ears - great spying technique).  I think
we will see them invent more than just joke material.  Any
thoughts?  If this has already been covered, I apologize.

Carla