I'm confused. In this day of new shapes and categories of pipe (Egg, Volcano, Horn, etc) I find it hard to keep up. One question I have is when does a Dublin become a Calabash and vice versa. Is there a "rule of thumb" or some standard? What is a "double" calabash. I have always thought of the Calabash as a gourd pipe with a meerschaum bowl that used to be referred to as a "Sherlock Holmes" style. Now I find wooden full-bent styles called "calabash".