The average reader who reads 2-300 words a minute does not read in a smooth, continuous flow, one word after another.
In actuality, the reader's eye will start out reading the first word, then the next, and then it will wander to another line on the page and then go back to where it left off. After reading a couple of more words in the sequence, the eye will retrace words that have already been read, then it will jump to a totally new line, and so on.
Most readers are compelled to go back over material that has already been "read" to make sure that it has been understood correctly. This is called back skipping and regression. This is why websites are designed to be more user-friendly to readers who scan rather than read word for word. Text is broken up using sections and unordered lists to make it easier for people to read.
I'm sorry I misunderstood what you were looking for- Are these the sort of patterns you were referring to?
http://www.poynterextra.org/eyetrack2004/viewing.htm - scroll about 1/3 down for a diagram
These articles may be of some use:
http://www.diku.dk/~panic/eyegaze/node17.html -Figure 8