Too many topics, too little time

Parlor Trick. I've just acquired a container of Geneva Magview, which is basically a magnetic suspension in aerosol form. Spray it on the magnetic strip of a Metro fare card or a 3.5″ disk exumed from its plastic housing and–violla–the pattern of… [Matthew G. Kirschenbaum]

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the problem of course is the pattern has no relationship to the meaning of the data, it is just noise unless you are dealing with analog data.