Extensions for the Amida-kuji Problem
Efficiency: "Worst Case" Assignment
                   For an amida-kuji with a certain number of players, what 
                    is the maximum number of horizontal lines you would ever 
                    need to create an ordering?  If you think of horizontal 
                    lines as having a cost, that number is considered the "worst 
                    case" number.  What is the worst case for 2 
                    players?; for 3 players?; for n players? 
Sorting Networks
                   If each horizontal line is thought of as a "sorting 
                    element" that is activated only when the number on the 
                    left is greater than the number on the right, then a "network 
                    lottery" turns into a "sorting network."   Computer 
                    scientists have done quite a bit of research on sorting networks.  However, 
                    most networks normally allow comparisons between nonadjacent 
                    lines, as in the figure below.  It is the most efficient 
                    network that is know  for sorting 13 items.  The 
                    sorting networks we get from amida-kuji are planar 
                    sorting networks, because the networks can be drawn on 
                    the plane without any lines crossing. 

For non-planar sorting networks, see http://unplugged.canterbury.ac.nz/sortnet/index.htm