Fig. 8: Three cages used during the experiments.

A Streamlined, disc-shaped cage with low-friction shell. B Streamlined, disc-shaped cage with high-friction shell. C Non-streamlined, squared cage with low-friction shell.

A Streamlined, disc-shaped cage with low-friction shell. B Streamlined, disc-shaped cage with high-friction shell. C Non-streamlined, squared cage with low-friction shell.