One consults the I Ching by generating the lines of a hexagram while holding a question in mind. Two traditional methods involve manipulating a bundle of 50 yarrow stalks or tossing three coins to generate a number in the range 6-9 for each of the six lines of the hexagram. The individual numbers designate:
    changing to unbroken 
    
    
    
    changing to broken 
    The lines are generated and ordered from bottom to top; the bottom line is "the beginning" or "in the first place", the line above it is "in the second place", and so on up to the line "at the top" or "in the sixth place".
The hexagrams are numbered in a traditional
    ordering that is somewhat obscure, although it pairs hexagrams
    whose lines are opposites or reversed in order.  A hexagram is
    composed of two trigrams which are
    associated with particular attributes and natural phenomena.  The
    text has a judgement giving the overall meaning of the
    hexagram, an image often metaphorically related to the component
    trigrams, and a section for each changing line.  A line marked with
    a circle 
 is considered a
    "governing ruler" of good character.  A line marked with a square
    
 is the "constituting
    ruler" that gives the hexagram its characteristic meaning, but is not
    necessarily of good character.  If any lines are changing, then the
    hexagram resulting from the changes is also presented.  Since there
    are six lines each with four possible states, there are 4096 possible
    readings that can be generated.
The coin method of casting a hexagram is simulated. The question typed in (if any) is used to influence the output of a random number generator along with other current circumstances.
The base URL http://hexadecimal.uoregon.edu/cgi-bin/ching will produce a random I Ching reading. Appending a question mark and six digits each in the range 6-9 will give the reading for that specific casting. Example: http://hexadecimal.uoregon.edu/cgi-bin/ching?899876.