Sweeping.

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After the stone is delivered, its trajectory is still influenced by the two sweepers under instruction from the skip. Sweeping is done for several reasons: to reduce friction underneath the stone, to decrease the amount of curl, and to clean debris from the stone's path. The stones curl more as they slow down, so sweeping early in travel tends to increase distance as well as straighten the path, and sweeping after sideways motion is established can increase the sideways distance. When sweeping, pressure and speed of the brush head are key in slightly increasing the layer of moisture that builds up under the stone.