Overview of the testing arena and the apparatus.

<p><b>(A)</b> Sketch of the testing arena viewed from the top, including the apparatus and the speakers; <b>(B)</b> Sketch of the apparatus viewed from the side, including the camera, the light, the plastic tube and the trough. In bold topography, a part of the material used for punishments, including the tennis ball relied on a fishing line, the air compressor relied on an air spray gun and a water spray gun; <b>(C)</b> Picture of the apparatus viewed from the front; <b>(D)</b> Picture of the apparatus viewed from the top with a piglet at the trough.