Another (pseudo-pseudo-random) way:

    perl -le 'print+time%2?"--":"++"'
[download]

Or if you weren't doing all of your voting at the same time:

    perl -le 'print$$%2?"--":"++"'
[download]

Anyone who has never voted on a node just to see its rep feel free to ignore this one as well, or use the following instead:

    perl -le 'print pack h2h2,b2,b2'
[download]

--
John.