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1. The prohibition of doing a mundane act even if no actual prohibited work is involved:
However, one who cuts [the wood] into big pieces and is not meticulous about their size, then it only contains a Rabbinical prohibition [which was prohibited] because it is a mundane action and [thus] disgraces the Shabbos. [This is prohibited even] when doing so does not contain the [prohibition of] moving Muktzah, such as by wood which was designated for a use and is [thus] prepared to be moved.
Does tearing a piece of paper into large pieces transgress the mundane act prohibition?
This matter requires further analysis. Nonetheless, this would be forbidden due to Muktzah, and perhaps the destroying prohibition.
 Admur 314:16