I recently read an article in Blade magazine re: Damascus steel.  One maker of pattern welded steel indicated that there were really only four types: random, twist, ladder and a fourth that I forgot (I don't have the article in front of me).  In my reading I have seen other types referred to: wootz, watered, 8-bar composite, wire, 1000 layered, etc. How many different types of Damascus are there in your opinion?
    Carlos Orellana

The term Damascus steel generally refers to steels having a visible pattern on the surface. Commonly, two very different procedures are used to make Damascus: Pattern welding and Wootz.
    
Pattern welded Damascus is formed using two or more different types of steel that are forge welded together. These layers are often folded several times to multiply the number of layers. Then the layers are manipulated in various ways to achieve different surface patterns.
    
It is not necessary to use flat bars for pattern welding. . Round and square bars are often bundled and welded together to achieve various surface patterns. Even EDM machinery is used to cut different shapes out of the parent materials which are then forge welded together. These more advanced welding and patterning techniques are commonly referred to as "mosaic Damascus". Mosaic Damascus can mean many things to many people. It is best to ask the maker about the specifics of the patterning..
    
The visual patterns available in pattern welded Damascus are endless. Your list above is a list of visual patterns formed by manipulating the layers in pattern welded Damascus.
        
Wootz is formed by melting iron in a crucible. Carbon is then added to the melted iron. Temperature and time control are critical. Careful forging of the resulting product will yield bars of steel where the cementite, iron carbide, has segregated out into visible layers.