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This java applet is a simulation of waves in a circular membrane (like a drum head), showing its various vibrational modes. To get started, double-click on one of the grid squares to select a mode (the fundamental mode is in the upper left). You can select any mode, or you can click once on multiple squares to combine modes.

Full Directions.

The source.

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Zip archive of this applet.

Version 1.6b, posted 2/3/14