Algodoo

I "think" what's happening here is Algodoo "attraction" attracts the center of mass of an object, unlike a magnet that can attract the end or any other portion of an iron object. That is why the rectangle on the right side is not affected by the attraction of the black circles. The circles are "pulling" on the center of the rectangle which happens to be anchored to the background with an axle. If you were to slide the axle toward the left end or right end of the rectangle, then it will rotate because one of the circles is tugging on the center of mass which is now between the axle and the end of the rectangle. And that is why the segmented rectangle on the left is attracted to the circles. The circles are tugging on each segment whose center of mass happens to be away from the axle anchor point. Attraction doesn't work like magnetism.... it seems to work like gravity!