July 23, 2010

The turn of a friendly card - Train numbering trick

Coming back from Orléans (France) on March 2010 for the Second conference  "Mathematics and Image processing" (Deuxième colloque "Méthodes mathématiques pour l’image") organized at MAPMO. Having presented stuff on Statistical estimators based on Stein's principle for  M-band wavelets and filter banks (abstract, slides, codes). Waiting in a train, staring again (and pixing) at the eight-seat compartment  numbering once discussed here

Since Igor Carron posted this Magic trick for summer vacations on Nuit Blanche (constest won by Laurent Jacques), I propose the following one again. Pictures attest the realness of the data, in contrast to Igor thought experiment (vicious tackle). Seat numbering is split in odd and even (unlike in six-seat cars), face-to-face, as:
.1 .3 .7 .5
.2 .8 .4 .6
The 3 (mod 8) sum is obvious. Easy enough for front-to-front booking by ancient computers. So why not the simple child Gauss-like arrangement?
.1 .3 .5 .7
.8 .6 .4 .2
Suspect some kind of compressive coding of seat booking? Contributions welcome. 

One good reason to listen on Nits again - The train. TGIF; my train of thoughts is leaving (le train de mes pensées s'égare).

Or Alan Parson's project - Turn of the friendly card: