As I walked down the aisle in the supermarket shopping for a particular brand of hot sauce, I realized the price differences among the more popular varieties. When I looked at the more expensive hot sauce brands I noticed something peculiar: the premium hot sauces have more distinctively shaped bottles. So I developed an intellectual property hypothesis right on the spot! (o.k. I need to get some hobbies…)
My Hypothesis: The more expensive and distinctive hot sauce bottles will have 3-D shape trademarks to secure their unique look and feel.
I later verified this (at http://www.uspto.gov) and found that the two more expensive brands with unique design features indeed have registered trademarks. The first one is the Cholula brand with a trademark on its distinctive wooden top. The other is the Tabasco brand with a trademark on its unique red cap and green label on the neck. The other brands listed below have no such packaging trademarks.
professororozco.com 
So 3D trademarks on bottles are no longer just for Pepsi and Coke. That’s really cool.
Andrew,
That’s right. 3D trademarks can apply to all sorts of bottles, as long as they are distinctive enough, e.g. having a uniquely shaped wooden top.