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ethicfail: Nature: No Photoshop required. 1. Lenticular Clouds 2. Anvil Clouds 3. Cirrus Kelvin-Helmholtz Clouds 4. Fallstreak Hole 5. Mammatus Clouds 6. Polar Stratospheric Cloud 7. Roll Cloud 8. Undulatus Asperatus 9. Mammatus Clouds 10. Undulatus