I once was obssessed with Lego education set and
I bought more than two sets of the NXT2.0 .
Following the instructions of the Time Twister,
which is a digital clock, I spent about 3 days on this set.
The bricks vary a lot and I have to get them from Lego MOC sites.
This process took about 3 week to do so,
including the post and delivery from various locations in the EU.
After seeing the completed module,
it's all worth it!
