Easter egg – Undocumented Matlab

Spy Easter egg take 2

Yair Altman — Wed, 04 Apr 2012 18:00:12 +0000

Three years ago, I posted a short post about Matlab’s built-in Easter egg in the spy function. Apparently, when running spy with no input arguments, it uses an undocumented default built-in sparse matrix that generates the white spy in the famous Spy vs. Spy comics series:

>> spy;

As was recently reported by Aurélien, the default built-in sparse matrix has changed in R2011a (not R2011b as in the original report):

If you ask me, the previous (white spy) image had more relevance to the spy function… I assume the new image was not chosen arbitrarily – if anyone has some insight as to why this image was chosen and its relevance to spy, please post a comment.
Addendum: The original spy image can still be generated using the following code snippet:



c = [';@3EA4:aei7]ced.CFHE;4\T>*Y>,dL0,HOQQMJLJE9PX[[Q.ZF.\JTCA1dd'

     '-IorRPNMPIE-Y\\R8[I8]SUDW2e+'

     '=4BGC;
     ':5CHD<=4hlh`f11EFPKHA7&WH-\J/gOC?kqtTRRORQJ8--^TB+T=dWYWY;,_'

     ';6D3E=>7imiag2IFOQLID8''XI.]K0"PD@l32UZhP//P988_WC,U>+Z^Y\<2`'

     '<82BF>?8jnjbhLJGPRMJE9/YJ/`L1#QMC$;;V[iv09QE99,XD.YB,[_\]=3a'

     '>9;CG?@9kokc2MKHQSOKF:0ZL0aM2$RNG%AAW\jw9E.FEE-_G8aG.d`]_W5+'

     '?:CDH@A:lpld3NLIRTPLG=1[M1bN3%SOH4BBX]kx:J9LLL8`H9bJ/+d_dX6,'

     '@;DEIAB;mqmePOMJSUQMJ>2\N2cO4&TPP@HCY^lyDKEMMN9+I@+S8,+deY7^'

     '8@EFJBC<4rnfQPNPTVRNKB3]O3dP5''UQQCIDZ_mzEPFNNOE,RA,T9/,++\8_'

     '9A2G3CD=544gRQPQUWUOLE4^P4"Q6(VRRIJE[`n{KQKOOPK-SE.W:F/,,]Z+'

     ':BDH4DE>655hSRQRVXVPMF5_Q5#R>)eSSJKF\ao0L.L-WUL.VF8XCH001_[,'

     ';3EI
     '?4D3=FP@877jUTSTXZXROK7%S7(TF+gUUmMR^cq:N9Q8YZQ9_I>cIJEB>d_^'

     '@5E@>GQA98b3VUTUY*YSPL8&T>)UI,hVhnNS_dr;PE.9Z[RCaR?+JTFC?e`+'

     '79FA?HRB:9c4WVUVZ+ZWQM=,WG*VJ-"gi4OT`es
     '8:3B@JSX;:dVXWVW[,[XRN>-XH+bK.#hj@PUvftDRMEF,]UH,UB.TYVWX,e\'

     '9;ECAKTY<;eWYXWX\:)YSOE.YI,cL/$ikCqV1guE/PFL-^XI-YG/WZWXY1+]'

     ':AFDBLUZ=
     ';B3ECMV[>jgY[ZYZ-<7[XQG0[K.eN1&"$K2u:iyO9.PN9-_K8aJ9\_]\]82['

     '?CEFDNW\?khZ\[Z[==8\YRH1\M/!O2''#%m31Bw0PE/QXE8+R9bS;da^]_93\'

     '@2FGEOX]ali[]\[\>>9(ZSL2]N0"P3($&n;2Cx1QN9--L9,SA+T<+d__`:4,'

     'A3GHFPY^bmj\^]\]??:)[TM3^O1%Q4)%''oA:D0:0OE.8ME-TE,XB,+`da;5['

     '643IGQZ_cnk]_^]^@@;5\UN4_P2&R6*&(3B;E1<1PN99NL8WF.^C/,a+bY6,'

     '7:F3HR[`dol^`_^_AA<6]VO5`Q3''S>+'');CBF:=:QOEEOO9_G8aH6/d,cZ[Y'

     '8;G4IS\aep4_a`_-BD=7''XP6aR4(T?,(5@DCHCC;RPFLPPD`H9bJ70+0d\\Z'

     '9BH>JT^bf45`ba`.CE@8(YQ7#S5)UD-)?AEDIDDD/QKMVQJ+S?cSDF,1e]a,'

     ':C3?K4_cg5[acbaADFA92ZR8$T6*VE.*@JFEJEEE0.NNWTK,U@+TEG0?+_bX'

     ';2D@L9`dh6\bdcbBEGD:3[S=)U7+cK/+CKGFLIKI9/OWZUL-VA,WIHB@,`cY'];

i = double(c(:)-32);

j = cumsum(diff([0; i])<=0) + 1;

S = sparse(i,j,1)';

spy(S)

Happy Easter / Passover everybody!

The post Spy Easter egg take 2 appeared first on Undocumented Matlab.

Image Easter egg

Yair Altman — Tue, 06 Apr 2010 17:28:44 +0000

Last year I presented the Matlab Spy Easter egg for the 2009 Easter holiday. This year, slightly late, I present another Easter egg in the well-known image function: When we run image with no input arguments, we get a default image of an inverted boy:

image;

Default image

To see the image right-side up:

image;
colormap(gray(32));
axis ij image off

Corrected default image

In fact, it turns out that there are quite a few hidden super-imposed images here, and that there is an interesting story behind them, which was explained by Steve Eddins in his Image Processing blog. For those interested, the boy above is Steve’s eldest, but that’s only a small part of the story…
Happy Holiday!
Yair
p.s. – The default image has not changed in many years. I guess the boy should be in high school or college by now. Perhaps it’s time to post an updated picture in the R2010b release, Steve?

The post Image Easter egg appeared first on Undocumented Matlab.

Spy Easter egg

Yair Altman — Sat, 11 Apr 2009 18:24:33 +0000

For the 2009 Easter holiday, I thought I’d post a Matlab Easter egg, which I found on http://www.eeggs.com/items/47352.html: spy is a built-in stock Matlab function for visualizing sparse matrices. If you run spy with no input arguments, it uses an undocumented default built-in sparse matrix that generates one of the spies in the famous Spy vs. Spy comics series:

spy;

The post Spy Easter egg appeared first on Undocumented Matlab.

Easter egg – Undocumented Matlab

Spy Easter egg take 2

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Image Easter egg

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Spy Easter egg

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