Contours teaching, a lot to learn

Taken out of the box these contours teaching was hard to use.
Firstly, it was very difficult, for other imprecise,
ie at a contour decrease attracted the plastic plates adjacent platelets.
What was it?
After removing the cover and removing the red plastic plate I looked at the matter a little more closely:
I took a stack of 10 tiles, as they came out of the contours teaching, and have even measured it with the calliper both ends.
The result was quite surprising:
There were only 10 plates already a difference of one millimeter ...
What was to be done?
On each slide you can see a small whitish Gating out of production.
You have to arrange these points always mutually set so once on the right, the other times to the left side
to balance out the thickness differences of platelets.
So reassembled (with platelets less) the thing worked pretty neat

My Conclusion:
To use out of the box bad
After the "reconstruction-measure" a satisfactory result