waitaminnit...
That site says "The BMW Art Cars series began in 1975 when the company commissioned Alexander Calder to paint a car for the 24 Hours of Le Mans."
I thought the Calder CS was commissioned for Herve Poulain... that car was my wallpaper at work for yearsandyearsand years. Now I have a late-70s shot of Kaimu Bay where I spent many an hour in my misspent surfing youth. Kaimu lies under 20 feet of still-hot lava, since '84. Considerably rarer than some old car, but...