A Barcode Solution

An obvious question is whether the +ORC Riddle, where it refers four times to "bars", is telling us that the solution is to be found in some sort of barcode.

+ORC has provided a tutorial on barcodes in one of his lessons (C1).

So let's explore that and see if anything turns up.

Take a look at the URL: . It has ten digits, and three periods separating them. As The Joker points out, this makes thirteen characters, the number of digits in an EAN barcode.

There are dozens of different barcode systems, but it makes sense to look at the EAN system as it is the one that +ORC has used in his tutorial. There's no obvious reason for choosing an alternative. (See here for some information on other systems. +ORC is right: there's a lot of stuff about barcodes on the Web, and nearly all of it is junk.)

So. Let's assume that it is meant to be an EAN barcode. That scheme only allows numerical digits. Again, let us assume the 'periods' can be read as zeros. Seems a reasonable assumption.

This gives us a barcode numerical sequence: 1 31092 015012 8 . In barcode parlance, the "pattern" for the first six digits (131092) is pattern "1", and the Checksum digit is "8".

The pattern is not much help here, as it only applies to the choice of character set used to display the particular number as a printed barcode. It doesn't affect the numerical sequence values. (I thought there might be something here initially, but I was wrong).

What might affect things is the Checksum digit.

Following the +ORC barcode tutorial, the sum of the six 'even' digits (#0, #2, #4 etc) is:

1+1+9+0+5+1 = 17

And the sum of the six 'odd' digits is:

3+0+2+1+0+2 = 8 .

Multiply this by 3 and add the sum of the 'evens' gives:

3*8 + 17 = 41 .

Take the modulo 10 of this: it gives the answer '9'. This says the checksum digit should be '9', not '8'. Making this change gives us the barcode sequence:

1 31092 01512 9 .

The sequence is now a self-consistent EAN barcode.

Converting the zeros back to periods gives us the 'corrected' URL:

There's only one problem. It doesn't work. Pity about that.

Looks like another dead end. Perhaps it has given you some ideas, though? Let me know.

[Message to +ORC: stop laughing. This is serious.]

the Basilisk

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