[kach22i]

https://citroenvie.com/proof-that-bertoni-applied-kamm-tail-benefits-to-the-sleek-ds/

While researchers including Kamm found that abruptly cutting off the tail resulted in minimal increase in drag, knowing that the ideal shape to minimize drag is a teardrop, Bertoni was obsessed with achieving that while still incorporating practicality in design. (As these evolutionary examples of the Traction Avant morphing into the eventual DS shape 20 years later illustrate.)