Vibrating membrane in MATLAB on a Titan

After exchanging some mail with Cleve Moler, inventor of MATLAB and founder of The Mathworks, I set out to recreate the Doré-rendered vibrating L-shaped membrane that he talks about in his blog here: https://blogs.mathworks.com/cleve/2013/12/09/the-ardent-titan-part-2/. This is a first attempt...