makeTestTree maxwidth height width tail =
  do
    branch <- makeTestTree maxwidth (height - 1) maxwidth []
    makeTestTree maxwidth height (width - 1) $! (branch : tail)
makeTestTree maxwidth height width tail =
  do
    branch <- makeTestTree maxwidth (height - 1) maxwidth []
    makeTestTree maxwidth height (width - 1) $! (branch : tail)
makeTestTree maxwidth height width tail =
  do
    branch <- makeTestTree maxwidth (height - 1) maxwidth []
    makeTestTree maxwidth height (width - 1) $! (branch : tail)