Fig. 2.
Symmetry variance in 2D heatmaps. Two experimental examples illustrate how a difference in symmetry is reflected in the heatmaps. The white line shows perfect symmetry, while the black-dashed line shows the corresponding line of the estimated slope β0. We can see that in the healthy froglet both black and white lines are almost the same, giving a β0 almost equal to 1. On the other hand, in the hemisected froglet the right foot tends to move approximately half the distance of the left foot's stroke, making white and black lines differ significantly, thus showing a lack of symmetry.