s discussed in the <a href="example_ivp_recording_particle_velocity.html">Recording The Particle Velocity Example</a>). In this case, the recorded time-varying acoustic pressure is accessed as <code>sensor_data(rect_num).p</code>, where <code>rect_num</code> is the number of the rectangular region within <code>sensor.mask</code>. In this example, two rectangular regions are assigned to <code>sensor.mask</code>, so <code>rect_num</code> would be set to <code>1</code> or <code>2</code>. As the shape of the se