Corrections

1. On page 3, this example previously had (17,8,1,"Dd") for the last square, putting it below the minimum size of 2.

   > drawSquares [(2,2,5,"Aa"), (12,0,4,"Bb"), (9,5,3,"C "),
                  (17,8, 2 ,"Dd")]
   ............BBBB....
   ............BbbB....
   ..AAAAA.....BbbB....
   ..AaaaA.....BBBB....
   ..AaaaA.............
   ..AaaaA..CCC........
   ..AAAAA..C C........
   .........CCC........
   .................DD.
   .................DD.
   ....................