The other ends of the springs are attached to a data point. The spring constant K i equals the values of the i-th coordinate of the fixed point. Each data point is then displayed where the sum of the spring forces equals 0. All the data point values are usually normalized to have values between 0 and 1. For example if all n coordinates have the same value the data point will lie exactly in the center of the circle.
Most points lie close to the center implying equal forces.
However, introns lie closer to the center than exons. This symmetry needed to be corrected for some aspects of the data mining. Figure 4 Expanded X 8 Figure 4 represents the same data with a zoom factor of 8 and larger points. Notice that zooming produces points well outside the circle which is not possible with real springs. The explanation for the spreading of exons is that they are not as random as introns.