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What matlab easter eggs do you know?

Asked by Paulo Silva on 25 Feb 2011
Latest activity Commented on by Image Analyst on 27 Nov 2013

Please post the easter eggs that you have found so far if they aren't already posted by someone else.

Let's try to make a good Matlab easter egg list because it seems that there isn't one.

What should be posted:

  • Unexpected but intentional behaviour
  • Special things that the programmers left for us to discover
  • Extra code inside a function that can be used for other purposes
  • Hidden pictures and audio clips

What shouldn't be posted:

  • Repeated Easter Eggs, if someone already posted it please don't repeat
  • Bugs in functions that cause trouble and might be fixed in later versions
  • Matlab games that come with the program unless they aren't mentioned in the documentation (the games are in the other demos, try the xpbombs and fifteen, you can even see the code for both games)

7 Comments

David on 7 May 2013

Ok so here's a list of ones I've found. Some of these ARE Emulators, but I figure most will appreciate them anyway. (A lot of the above posts are random programs associated with emulators and gui's anyway.)

  1. fifteen (Let's you play sliding numbers game)
  2. why (just randomly generated responses)
  3. life (lets you play 'the game of life')
  4. image (that blue pic of the boy)
  5. shower (A program that let's you play with a shower.)
  6. step
  7. surf(membrane)
  8. imagesc(hot)
  9. logo
  10. cruller (3D image and is rotatable)
  11. census
  12. earthmap
  13. eigshow (rotates vectors on screen)
  14. imagesAndVideo (video of space shuttle take off)
  15. imageext (lets you see SEVERAL random images)
  16. knot (Another 3D image that's rotatable)
  17. lorenz (Don't even know, just cool)
  18. makevase
  19. truss (Bending modes of a truss)
  20. vibes (3D vibrating image)
  21. wrldtrv (Let's you plan world travel distances)
  22. xpquad (Changing quadratics of a cube)
  23. xpsound (Sound demo that includes Handel)
  24. eml_asteroids (Asteroids videogame emulator)
  25. eml_fire (Emulator that displays growing fire)
  26. sf_tictacflow (Tictactoe emulator)
  27. rlc_gui (RLC circuit analysis emulator)
  28. tetris_2 (Tetris)
David on 7 May 2013

Technically all of these are visible code you can look up and manipulate, so I'm not sure these count as Easter Eggs, but whatever. They're still pretty cool.

Forgot a couple, too.

  1. spy (but this was already mentioned also)
  2. load audio48, sound(signal48kHz, Fs48)

That last one plays some random rock band music

ENJOY!!

Sean de Wolski on 7 May 2013

@David, nice!

Paulo Silva

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8 Answers

Answer by Kenneth Eaton on 25 Feb 2011

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.

2 Comments

Paulo Silva on 25 Feb 2011

Hi Kenneth that's very cool, +1 vote

Andrew Newell on 25 Feb 2011

What - no image of Satan?

Kenneth Eaton
Answer by Paulo Silva on 25 Feb 2011

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

6 Comments

Sean de Wolski on 25 Feb 2011

I wrote two functions:
lala.m
and lalala.m
lala displays: "stop singing and get back to work"
and lalala sounds handel. It makes for fun giving those to others in the lab.

Paulo Silva on 25 Feb 2011

Hey Sean that's good fun but I wonder if the nice people from mathworks did include something similar but no one found it yet, are they forbid to do that?

Image Analyst on 26 Jan 2012

Paulo, your avatar is no longer the "spy" image that pops up - it's Sean's dog (I think). Sean's lalala function is not in R2011b - maybe it will come out in R2012a.

Paulo Silva
Answer by Andrew Newell on 25 Feb 2011

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?

5 Comments

Michelle Hirsch on 25 Feb 2011

Oh, but there is so much more to image than meets the eye!! Let's see who can find what else is hidden there :)

Paulo Silva on 25 Feb 2011

Hi Scott, without being able to see the code for image it's not easy :(

Sean de Wolski on 25 Feb 2011

Paulo, search Steve Eddin's Blog for 'image function' (or similar). There is quite a lot to learn there!

Andrew Newell
Answer by Paulo Silva on 5 Mar 2011

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

0 Comments

Paulo Silva
Answer by Saurav Kumar on 25 Apr 2011

surf(membrane) gives mathworks logo

imagesc(cool) gives the cool colors

imagesc(hot)

1 Comment

Image Analyst on 26 Jan 2012

So does "logo"

Saurav Kumar
Answer by Image Analyst on 26 Jan 2012

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.

0 Comments

Image Analyst
Answer by Ming on 25 Oct 2013

There are two that I know from old versions of MS-DOS Matlab:

  • fuck -> you place or mine?
  • lala -> quit singing and get back to work

0 Comments

Ming
Answer by Dennis Jaheruddin on 27 Nov 2013

Not sure if it is really an easter egg, it is a bit simpler than most others.

The description of this function surprised me:

  • eomfun

Note that it is only found in the help, not in the doc.

1 Comment

Image Analyst on 27 Nov 2013

Easter eggs come and go. It's not in release R2013a. What version did you verify it in?

Dennis Jaheruddin

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