What is the pendulum wave?

Hint: A wave is a propagating dynamic disturbance (change from equilibrium) of one or more quantities in physics, mathematics, and related areas, frequently represented by a wave equation. At least two field quantities in the wave medium are involved in physical waves.

Complete answer:
The Pendulum Wave is made up of a succession of pendulums with increasing durations that, when released all at once, create the illusion of a shifting transverse wave that returns to its original state. This gadget has a hypnotic effect because it has a succession of pendulums with increasing time periods that, when released all at once, generate a wave effect. In this scenario, the wave shrinks in wavelength, then seems highly chaotic before returning to the straight line from which it began. Each pendulum's lengths are connected to the one next to it in such a way that after a given amount of swings, they are back in phase.
Pendulum: a body hanging from a fixed point that swings back and forth under gravity's effect. Pendulums are used to control the movement of clocks because the period, or time interval, for each full oscillation is constant. A pendulum wave is a gadget that consists of a sequence of pendulums with progressively longer periods of time. When these pendulums are released at the same time, they create a transverse wave that keeps shifting and eventually returns to its original position.

Note:
A physical wave is nearly always contained inside a limited spatial region known as its domain. Earthquake seismic waves, for example, are only relevant in the planet's interior and surface, thus they may be ignored everywhere. Infinite domain waves, on the other hand, are frequently studied in mathematics and are extremely useful tools for understanding physical waves in finite domains.