Vibrating Membrane

One of these systems can be simulated by a plane of masses connected by springs, as shown in next figure. In this membrane, all bordering particles are fixed. The fundamental vibration mode, that emerges when you perturb the central point of the membrane, is shown.

In the following animation a membrane forced to vibrate by a spring mass oscillating system is shown.

You can stop the animation, delete the particle (click on the particle with the left mouse button and select "delete particle") and animate again. You will observe the transfer of energy from the original mode to many other modes in a very complex way.