Creating Duplicate Objects in 3-Space

Here, we illustrate how the [b]absolute value function[/b] can easily allow us to create duplicate surfaces in GeoGebra 3D Graphing Calculator. Here, we illustrate in GeoGebra Augmented Reality. [br][br]How can we describe any symmetries (plane, rotational) seen here?
1 Paraboloid
2 Paraboloids: Notice the |x| term in the equation below.
2 Paraboloids: Notice the |y| term in the equation below.
4 Paraboloids: Notice the |x| and |y| terms in the equation below.
Quick (Silent) Demo

Information: Creating Duplicate Objects in 3-Space