How to draw text in boxes

boxletter.py

from PIL import ImageDraw, Image, ImageFont

BLACK = (0,0,0)
WHITE = (255,255,255)
LTBLUE = (192,192,255)

fig = Image.new( "RGB", (320,320), WHITE )
arial = ImageFont.truetype("../.fonts/arial.ttf", 32 )

y = 100

def drawboxstring( img, s, y ):
    xleft = (fig.width - 50*len(s)) // 2
    d = ImageDraw.Draw(img)
    for c in s:
        d.rectangle( ((xleft, y), (xleft+50,y+50)), outline=BLACK, fill=LTBLUE )
        d.text( (xleft+12, y+10), c, font=arial, fill=BLACK )
        xleft += 50

drawboxstring( fig, "AB", y )
y += 50
drawboxstring( fig, "CDE", y )
y += 50
drawboxstring( fig, "FGHI", y )
fig.save( "abc.png" )

Here's the output: