Geological diagrams for 3D motion

Science, May 16, 2003, shows some interesting geological diagrams for describing 3D slippage. Can someone who knows the field please provide a careful explanation of the ball diagrams in these figures?

Figure 2 from David Bowman, Geoffrey King, Paul Tapponnier, “Slip Partitioning by Elastoplastic Propagation of Oblique Slip at Depth”, Science, Vol. 300 (May 16, 2003), pp. 1121-1123.

Figure 2 from Donna Eberhart-Phillips, et al., “The 2002 Denali Fault Earthquake, Alaska: A Large Magnitude, Slip-Partitioned Event”, Science, Vol. 300 (May 16, 2003), pp. 1113-1118.