I reminds me roughly of a code I came up with when I was a kid, which was actually based on Morse code. You'd write the plaintext out in Morse, and create one series of numbers representing the # of dots&dashes in each letter, then a second series of numbers counted consecutive dots and dashes. So Slashdot would be
Morse: Filter doesn't like :(
Code2: 41317124 ...and you could throw random numbers above 4 in the first line as noise. Simple enough you could do it on paper (assuming you already knew morse). I forget how I designated whether the first thing was a dot or a dash.
I can't help wondering if it's something along these lines.