What matlab easter eggs do you know?

As Steve discussed in one of his blog posts, the default image in MATLAB is actually a steganographic image:

image

Just looks like an upside-down little boy, right? Well, if you rotate the 53-bits of the double precision fraction component so that each becomes the highest valued bit, you can easily see the hidden images:

Here's how I made the above image:

defImage = pow2(get(0,'DefaultImageCData'),47);
imgCell = repmat({zeros(size(defImage))},8,7);
for shift = 0:52
  imgCell{shift+1} = bitrotate(defImage,shift);
end;
allImages = cell2mat(imgCell.');
imshow(allImages,[min(allImages(:)) max(allImages(:))]);

NOTE: bitrotate is a version of the built-in bitshift that I wrote to perform a circular shift of the bit pattern instead of discarding bits that overflow. I'll be placing bitrotate on the FEX soon, but for now you can just replace it with bitshift in the above code.

The spy function without arguments makes a cool figure (my current avatar).

The why function says random things.

Matlab comes with a great sound clip for those moments when you find a solution for a huge problem

load handel
sound(y,Fs)

The pie function (matlab 2008b and maybe later versions) doesn't allow to place the labels in a specific place but in the function code there's a variable that allows the text to be inside the pie and you might also set the distance from the center of the pie, here's a little hack that I did to pie

This site and this site have several Easter eggs, but most don't work on 2010b. Just these work for me:

image
penny
shower

But are these really Easter eggs or just demos?

Today I found that these functions:

step 

impulse

From the Control System Toolbox work without any arguments, there's a sort of demo that they make, very nice, I was using them for years without noticing, nice surprise, wonder why the tf function doesn't also have the same behaviour

surf(membrane) gives mathworks logo

imagesc(cool) gives the cool colors

imagesc(hot)

Not sure if they qualify as Easter eggs, but type these on the command line (verified on R2011b):

1. why
2. why are there too many input arguments?
3. xpbombs
4. fifteen
5. spy (new image is probably only version R2011b or later - clearly Sean has had some influence since he joined the Mathworks staff)
6. x=[-2:.001:2],y=(sqrt(cos(x)).*cos(200*x)+sqrt(abs(x))-0.7).*(4-x.*x).^0.01,plot(x,y);

On http://www.walkingrandomly.com/?p=2949, Cleve says " As our code base has increased, including such goodies in the MATLAB core has become problematic because of the strain it puts on rigorous automated testing. It is still possible to include them in a few “leaf” M functions, like “spy”, that other functions do not depend upon." so they will probably be fewer as time goes on.