A Lego 9 Volt Micromotor is used to create the wiggling action, by pushing and pulling on the right rear corner of the front half of the vehicle. The central joint is quite well reinforced to allow only the simple horizontal pivoting of the two halves. If this joint is too loose, the vehicles overall forward motion will be reduced. This joint is smooth, but only allows for motion in the plane of the table (road surface).
It is important to note that there are separate axles for each wheel. If solid axles were placed across the front and/or back, the vehicle would not be able to move, each of the four wheels must be allowed to move independently of all others.
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