Is there a roof rain diverter that fans the water outward?

I don't have gutters on my house, but the roof has several valleys where rainwater collects and pours off into the lawn or garden, pounding the ground and digging holes or damaging plants. I thought somewhere I'd once seen an ad for a device that would fit into the "corner" of the roof edge where the valley comes down and sort of "fan" the water out so it falls to the ground like rain.

Does this ring a bell with anyone? Does something like this exist?

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