(submitted by jim) One winter about 17 years ago we drove from Melbourne to Adelaide via the coast. Some of the side trips were over unsealed roads and the second attachment records the result. The ribbed lenses indeed work as Stuttgart intended. The effect was actually more pronounced in reality hence taking the photograph.
We still have the car today; it’s just clocked 324K kms, and the little guy pictured in the rear is about to turn 20.