Movie 3.

Potential energy landscape model. Part 1. Pitch-to-roll transition on pitch-roll cross section. Part 2. Roll-to-deflect transition on yaw cross section. Top left: model of cockroach traversing beam obstacles at head flexion β_h = 15° with hind legs neglected. Top right: potential energy landscape pitch-roll cross section (part 1) or yaw cross section (part 2) along the average animal trajectory. Blue, red, and purple dots are pitch, roll, and deflect local minima, respectively. Orange dots are saddle points. Green curves are imaginary routes. Bottom left: Potential energy along the imaginary route. Bottom right: Potential energy barrier as a function of forward position x.