These are known as 'Zig-Zag Roulettes'.
As mentioned by Bobby De La Rue above, the zig-zag rouletting proved unsatisfactory.
Scudder (RPSV, 2013) informs us that "the sheets were difficult to separate and at the same time tended to fall apart" and were returned to the lithographic office for perforation, as seen on the stamp at the top of this thread.
There are seven different configurations of coloured and plain roulettes with and without perforations added.
They are a very interesting part of Queensland postal history.
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Used examples must be hard to find.
This is borne out by the catalogue prices of the rarer configurations - they are higher than the mint prices.