Product Idea

LEGO Friends' Bumper Cars

Build this for someone you love.
As a father of a 5-year girl, I have won her heart and let her go nut. You may do the same to your daughters/lover/fiance/wife.
Another facility of my Friends' theme park. I wish not only girls love it, but also boys do. The build is a little complex and obviously it is beyond the ability of young girls. However, you can build this as a gift to someone meaningful to you.
Click here for its movie.
Click here if you want to know further how it works.

The girls like to bump the others. Sometimes it can be a head-to-head bump.

The bumper cars are driven by magnets underneath.

(Left) The turntable are installed with many magnets and they determine how the bumper cars move.
(Right) Each car is installed with a magnet and two wheels to the effect that the car will roll forward but not backward.

My idea of building the turntable is actually a modification of 10196.
There are wheels (A) which supports the baseplate above. Mind you, the 8 cars above are heavy and the baseplate above, under pressure, can lead to too much friction with the turntable and so that the turntable does not move. Now these wheels solve this problem entirely.
You may have seen the panoramic view of the turntable in the previous photo. There are many fixed magnets (B).
In order to create a delaying effect and make the cars bump with each other, magnet (C) is movable.
If you have watched the attached video above, hopefully you should have a clear understanding of my words here.