diff --git a/pdfminer/layout.py b/pdfminer/layout.py
index 99807b2..7037fe7 100644
--- a/pdfminer/layout.py
+++ b/pdfminer/layout.py
@@ -81,14 +81,15 @@ class LTComponent(LTItem):
         return ('<%s %s>' %
                 (self.__class__.__name__, bbox2str(self.bbox)))
 
-    def set_bbox(self, (x0, y0, x1, y1)):
+    def set_bbox(self, bbox):
+        (x0, y0, x1, y1) = bbox
         self.x0 = x0
         self.y0 = y0
         self.x1 = x1
         self.y1 = y1
         self.width = x1-x0
         self.height = y1-y0
-        self.bbox = (x0, y0, x1, y1)
+        self.bbox = bbox
         return
 
     def is_empty(self):
@@ -158,7 +159,8 @@ class LTLine(LTCurve):
 ##
 class LTRect(LTCurve):
 
-    def __init__(self, linewidth, (x0, y0, x1, y1)):
+    def __init__(self, linewidth, bbox):
+        (x0, y0, x1, y1) = bbox
         LTCurve.__init__(self, linewidth, [(x0, y0), (x1, y0), (x1, y1), (x0, y1)])
         return
 
diff --git a/pdfminer/pdfdevice.py b/pdfminer/pdfdevice.py
index 15fe80a..f6506f4 100644
--- a/pdfminer/pdfdevice.py
+++ b/pdfminer/pdfdevice.py
@@ -79,8 +79,9 @@ class PDFTextDevice(PDFDevice):
                 scaling, charspace, wordspace, rise, dxscale)
         return
 
-    def render_string_horizontal(self, seq, matrix, (x, y),
+    def render_string_horizontal(self, seq, matrix, pos,
                                  font, fontsize, scaling, charspace, wordspace, rise, dxscale):
+        (x, y) = pos
         needcharspace = False
         for obj in seq:
             if isnumber(obj):
@@ -97,8 +98,9 @@ class PDFTextDevice(PDFDevice):
                     needcharspace = True
         return (x, y)
 
-    def render_string_vertical(self, seq, matrix, (x, y),
+    def render_string_vertical(self, seq, matrix, pos,
                                font, fontsize, scaling, charspace, wordspace, rise, dxscale):
+        (x, y) = pos
         needcharspace = False
         for obj in seq:
             if isnumber(obj):
diff --git a/pdfminer/utils.py b/pdfminer/utils.py
index f83f6cf..80c735c 100644
--- a/pdfminer/utils.py
+++ b/pdfminer/utils.py
@@ -54,25 +54,33 @@ def apply_png_predictor(pred, colors, columns, bitspercomponent, data):
 MATRIX_IDENTITY = (1, 0, 0, 1, 0, 0)
 
 
-def mult_matrix((a1, b1, c1, d1, e1, f1), (a0, b0, c0, d0, e0, f0)):
+def mult_matrix(m1, m0):
+    (a1, b1, c1, d1, e1, f1) = m1
+    (a0, b0, c0, d0, e0, f0) = m0
     """Returns the multiplication of two matrices."""
     return (a0*a1+c0*b1,    b0*a1+d0*b1,
             a0*c1+c0*d1,    b0*c1+d0*d1,
             a0*e1+c0*f1+e0, b0*e1+d0*f1+f0)
 
 
-def translate_matrix((a, b, c, d, e, f), (x, y)):
+def translate_matrix(m, v):
     """Translates a matrix by (x, y)."""
+    (a, b, c, d, e, f) = m
+    (x, y) = v
     return (a, b, c, d, x*a+y*c+e, x*b+y*d+f)
 
 
-def apply_matrix_pt((a, b, c, d, e, f), (x, y)):
+def apply_matrix_pt(m, v):
+    (a, b, c, d, e, f) = m
+    (x, y) = v
     """Applies a matrix to a point."""
     return (a*x+c*y+e, b*x+d*y+f)
 
 
-def apply_matrix_norm((a, b, c, d, e, f), (p, q)):
+def apply_matrix_norm(m, v):
     """Equivalent to apply_matrix_pt(M, (p,q)) - apply_matrix_pt(M, (0,0))"""
+    (a, b, c, d, e, f) = m
+    (p, q) = v
     return (a*p+c*q, b*p+d*q)
 
 
@@ -227,11 +235,13 @@ def enc(x, codec='ascii'):
     return x.encode(codec, 'xmlcharrefreplace')
 
 
-def bbox2str((x0, y0, x1, y1)):
+def bbox2str(bbox):
+    (x0, y0, x1, y1) = bbox
     return '%.3f,%.3f,%.3f,%.3f' % (x0, y0, x1, y1)
 
 
-def matrix2str((a, b, c, d, e, f)):
+def matrix2str(m):
+    (a, b, c, d, e, f) = m
     return '[%.2f,%.2f,%.2f,%.2f, (%.2f,%.2f)]' % (a, b, c, d, e, f)
 
 
@@ -264,7 +274,8 @@ class Plane(object):
     def __contains__(self, obj):
         return obj in self._objs
 
-    def _getrange(self, (x0, y0, x1, y1)):
+    def _getrange(self, bbox):
+        (x0, y0, x1, y1) = bbox
         if (x1 <= self.x0 or self.x1 <= x0 or
             y1 <= self.y0 or self.y1 <= y0): return
         x0 = max(self.x0, x0)
@@ -306,9 +317,10 @@ class Plane(object):
         return
 
     # find(): finds objects that are in a certain area.
-    def find(self, (x0, y0, x1, y1)):
+    def find(self, bbox):
+        (x0, y0, x1, y1) = bbox
         done = set()
-        for k in self._getrange((x0, y0, x1, y1)):
+        for k in self._getrange(bbox):
             if k not in self._grid:
                 continue
             for obj in self._grid[k]: