On your mark...

Let's place people in their starting position now and draw a pretty map showing people's happiness at the start... Here's the code for this:

  let starting_placement = zip centers people

  let mismatches :: Person -> Person -> Int 
      mismatches a b = length $ filter (uncurry (/=)) $ zip a b

  let similarityColor :: Person -> Person -> Color 
      similarityColor p1 p2 = let m = mismatches p1 p2   
                                  h = div (length p1) 2  
                                  d = 30 * (abs (h - m)) 
                                  b = max 0 (255-d)      
                                  o = min d 255          
                              in if m < h
                                 then (0,o,b)
                                 else (o,0,b)

  let findPerson :: Placement -> Point -> Person 
      findPerson a p | Just (_,e) <- find ((== p).fst) a = e

  let similarityLine :: Placement -> Link -> (Color,Polygon) 
      similarityLine l [p1,p2] = (similarityColor (findPerson l p1) (findPerson l p2),[p1,p2])

  writeFile "tut8.svg" $ writePolygons $ map (similarityLine starting_placement) sitting

Here's what tut8.svg looks like:

The only really important function in this block of code is the first line that calculates the starting_placement... This is just a zipped together list of the lot centers and people into spot-people pairs. The rest of the code is just for the eye candy...

The color of the lines tells you how well two neighbors get along... The similarityColor function is a little kludge that creates a nice color from red to blue, depending on how compatible two people are (as usual in Haskell, the type signature of Person->Person->Color is pretty much a dead give-away...)