diff --git a/gfxlcd/__init__.py b/gfxlcd/__init__.py
index 7c2d50b..3b83c1b 100644
--- a/gfxlcd/__init__.py
+++ b/gfxlcd/__init__.py
@@ -1 +1,2 @@
-__author__ = 'kosci'
+"""GfxLCD module"""
+__author__ = 'Bartosz Kosciow'
diff --git a/gfxlcd/abstract/__init__.py b/gfxlcd/abstract/__init__.py
index 7c2d50b..3dd8799 100644
--- a/gfxlcd/abstract/__init__.py
+++ b/gfxlcd/abstract/__init__.py
@@ -1 +1,2 @@
-__author__ = 'kosci'
+"""abstracts/interfaces"""
+__author__ = 'Bartosz Kosciow'
\ No newline at end of file
diff --git a/gfxlcd/demos/ili_2.py b/gfxlcd/demos/ili_2.py
index 6bc7fd1..4d8d91d 100644
--- a/gfxlcd/demos/ili_2.py
+++ b/gfxlcd/demos/ili_2.py
@@ -1,9 +1,9 @@
 import RPi.GPIO
 import sys
+import random
 sys.path.append("../../")
 from gfxlcd.driver.ili9325.gpio import GPIO as ILIGPIO
 from gfxlcd.driver.ili9325.ili9325 import ILI9325
-import random
 RPi.GPIO.setmode(RPi.GPIO.BCM)
 
 
diff --git a/gfxlcd/demos/nju_2.py b/gfxlcd/demos/nju_2.py
index 52483c0..7b593ac 100644
--- a/gfxlcd/demos/nju_2.py
+++ b/gfxlcd/demos/nju_2.py
@@ -1,9 +1,9 @@
 import RPi.GPIO
 import sys
+import random
 sys.path.append("../../")
 from gfxlcd.driver.nju6450.gpio import GPIO
 from gfxlcd.driver.nju6450.nju6450 import NJU6450
-import random
 RPi.GPIO.setmode(RPi.GPIO.BCM)
 
 
diff --git a/gfxlcd/demos/ssd_2.py b/gfxlcd/demos/ssd_2.py
index e01ca28..cc7d4b9 100644
--- a/gfxlcd/demos/ssd_2.py
+++ b/gfxlcd/demos/ssd_2.py
@@ -1,10 +1,10 @@
 import RPi.GPIO
 import sys
-RPi.GPIO.setmode(RPi.GPIO.BCM)
+import random
 sys.path.append("../../")
 from gfxlcd.driver.ssd1306.spi import SPI
 from gfxlcd.driver.ssd1306.ssd1306 import SSD1306
-import random
+RPi.GPIO.setmode(RPi.GPIO.BCM)
 
 
 def hole(o, x, y):
@@ -24,7 +24,10 @@ def hole(o, x, y):
 
 def draw_points(o):
     for _ in range(0, 50):
-        hole(o, random.randint(2, o.width-  10), random.randint(2, o.height-10))
+        hole(o,
+             random.randint(2, o.width - 10),
+             random.randint(2, o.height - 10)
+        )
 
 
 def draw_net(o):
diff --git a/gfxlcd/drawing/__init__.py b/gfxlcd/drawing/__init__.py
index 7c2d50b..d25812e 100644
--- a/gfxlcd/drawing/__init__.py
+++ b/gfxlcd/drawing/__init__.py
@@ -1 +1,2 @@
-__author__ = 'kosci'
+"""drawing module"""
+__author__ = 'Bartosz Kosciow'
\ No newline at end of file
diff --git a/gfxlcd/drawing/page.py b/gfxlcd/drawing/page.py
index 3ed8c57..6e6ca58 100644
--- a/gfxlcd/drawing/page.py
+++ b/gfxlcd/drawing/page.py
@@ -101,8 +101,8 @@ class Page(Pixel, metaclass=abc.ABCMeta):
 
         page = start_page
         for value in rows:
-            for x in range(pos_x2-pos_x1+1):
-                self.buffer[pos_x1+x][page] |= value
+            for x_diff in range(pos_x2-pos_x1+1):
+                self.buffer[pos_x1+x_diff][page] |= value
             page += 1
 
     def get_page_value(self, column, page):
diff --git a/gfxlcd/drawing/pixel.py b/gfxlcd/drawing/pixel.py
index f07383e..c2c22ac 100644
--- a/gfxlcd/drawing/pixel.py
+++ b/gfxlcd/drawing/pixel.py
@@ -5,6 +5,7 @@ import math
 class Pixel(object):
     """Pixel class"""
     def __init__(self, driver):
+        self.driver = driver
         self.options['color'] = {
             'R': 255, 'G': 255, 'B': 255
         }
@@ -20,27 +21,27 @@ class Pixel(object):
         """dummy fuction"""
         pass
 
-    def draw_rect(self, x1, y1, x2, y2):
+    def draw_rect(self, pos_x1, pos_y1, pos_x2, pos_y2):
         """draw a rectangle"""
-        self.draw_line(x1, y1, x2, y1)
-        self.draw_line(x1, y2, x2, y2)
-        self.draw_line(x1, y1, x1, y2)
-        self.draw_line(x2, y1, x2, y2)
+        self.draw_line(pos_x1, pos_y1, pos_x2, pos_y1)
+        self.draw_line(pos_x1, pos_y2, pos_x2, pos_y2)
+        self.draw_line(pos_x1, pos_y1, pos_x1, pos_y2)
+        self.draw_line(pos_x2, pos_y1, pos_x2, pos_y2)
 
-    def draw_circle(self, x, y, radius):
+    def draw_circle(self, pos_x, pos_y, radius):
         """draw a circle"""
         err = 0
         offset_x = radius
         offset_y = 0
         while offset_x >= offset_y:
-            self.draw_pixel(x + offset_x, y + offset_y)
-            self.draw_pixel(x + offset_y, y + offset_x)
-            self.draw_pixel(x - offset_y, y + offset_x)
-            self.draw_pixel(x - offset_x, y + offset_y)
-            self.draw_pixel(x - offset_x, y - offset_y)
-            self.draw_pixel(x - offset_y, y - offset_x)
-            self.draw_pixel(x + offset_y, y - offset_x)
-            self.draw_pixel(x + offset_x, y - offset_y)
+            self.draw_pixel(pos_x + offset_x, pos_y + offset_y)
+            self.draw_pixel(pos_x + offset_y, pos_y + offset_x)
+            self.draw_pixel(pos_x - offset_y, pos_y + offset_x)
+            self.draw_pixel(pos_x - offset_x, pos_y + offset_y)
+            self.draw_pixel(pos_x - offset_x, pos_y - offset_y)
+            self.draw_pixel(pos_x - offset_y, pos_y - offset_x)
+            self.draw_pixel(pos_x + offset_y, pos_y - offset_x)
+            self.draw_pixel(pos_x + offset_x, pos_y - offset_y)
             if err <= 0:
                 offset_y += 1
                 err += 2*offset_y + 1
@@ -48,7 +49,7 @@ class Pixel(object):
                 offset_x -= 1
                 err -= 2*offset_x + 1
 
-    def draw_arc(self, x, y, radius, start, end):
+    def draw_arc(self, pos_x, pos_y, radius, start, end):
         """draw an arc"""
         start = start * math.pi / 180
         end = end * math.pi / 180
@@ -58,22 +59,22 @@ class Pixel(object):
         offset_y = 0
         while offset_x >= offset_y:
             if start <= math.atan2(offset_y, offset_x) <= end:
-                self.draw_pixel(x + offset_x, y + offset_y)
+                self.draw_pixel(pos_x + offset_x, pos_y + offset_y)
             if start <= math.atan2(offset_x, offset_y) <= end:
-                self.draw_pixel(x + offset_y, y + offset_x)
+                self.draw_pixel(pos_x + offset_y, pos_y + offset_x)
             if start <= math.atan2(offset_x, -offset_y) <= end:
-                self.draw_pixel(x - offset_y, y + offset_x)
+                self.draw_pixel(pos_x - offset_y, pos_y + offset_x)
             if start <= math.atan2(offset_y, -offset_x) <= end:
-                self.draw_pixel(x - offset_x, y + offset_y)
+                self.draw_pixel(pos_x - offset_x, pos_y + offset_y)
 
             if start <= math.atan2(-offset_y, -offset_x) + 2*math.pi <= end:
-                self.draw_pixel(x - offset_x, y - offset_y)
+                self.draw_pixel(pos_x - offset_x, pos_y - offset_y)
             if start <= math.atan2(-offset_x, -offset_y) + 2*math.pi <= end:
-                self.draw_pixel(x - offset_y, y - offset_x)
+                self.draw_pixel(pos_x - offset_y, pos_y - offset_x)
             if start <= math.atan2(-offset_x, offset_y) + 2*math.pi <= end:
-                self.draw_pixel(x + offset_y, y - offset_x)
+                self.draw_pixel(pos_x + offset_y, pos_y - offset_x)
             if start <= math.atan2(-offset_y, offset_x) + 2*math.pi <= end:
-                self.draw_pixel(x + offset_x, y - offset_y)
+                self.draw_pixel(pos_x + offset_x, pos_y - offset_y)
 
             if err <= 0:
                 offset_y += 1
diff --git a/gfxlcd/driver/__init__.py b/gfxlcd/driver/__init__.py
index 7c2d50b..9e335e9 100644
--- a/gfxlcd/driver/__init__.py
+++ b/gfxlcd/driver/__init__.py
@@ -1 +1,2 @@
-__author__ = 'kosci'
+"""driver module"""
+__author__ = 'Bartosz Kosciow'
\ No newline at end of file
diff --git a/gfxlcd/driver/ili9325/__init__.py b/gfxlcd/driver/ili9325/__init__.py
index 7c2d50b..95e8fad 100644
--- a/gfxlcd/driver/ili9325/__init__.py
+++ b/gfxlcd/driver/ili9325/__init__.py
@@ -1 +1,2 @@
-__author__ = 'kosci'
+"""driver/ili9325 module"""
+__author__ = 'Bartosz Kosciow'
\ No newline at end of file
diff --git a/gfxlcd/driver/nju6450/__init__.py b/gfxlcd/driver/nju6450/__init__.py
index 7c2d50b..01b79d8 100644
--- a/gfxlcd/driver/nju6450/__init__.py
+++ b/gfxlcd/driver/nju6450/__init__.py
@@ -1 +1,2 @@
-__author__ = 'kosci'
+"""driver/nju6450 module"""
+__author__ = 'Bartosz Kosciow'
\ No newline at end of file
diff --git a/gfxlcd/driver/nju6450/gpio.py b/gfxlcd/driver/nju6450/gpio.py
index 5605e95..b52d09b 100644
--- a/gfxlcd/driver/nju6450/gpio.py
+++ b/gfxlcd/driver/nju6450/gpio.py
@@ -1,6 +1,6 @@
 """NJU6450 gpio driver class"""
 import time
-import RPi.GPIO # pylint: disable=I0011,F0401
+import RPi.GPIO  # pylint: disable=I0011,F0401
 from gfxlcd.abstract.driver import Driver
 
 RPi.GPIO.setmode(RPi.GPIO.BCM)
diff --git a/gfxlcd/driver/ssd1306/__init__.py b/gfxlcd/driver/ssd1306/__init__.py
index 7c2d50b..31c4620 100644
--- a/gfxlcd/driver/ssd1306/__init__.py
+++ b/gfxlcd/driver/ssd1306/__init__.py
@@ -1 +1,2 @@
-__author__ = 'kosci'
+"""driver/ssd1306 module"""
+__author__ = 'Bartosz Kosciow'
\ No newline at end of file
diff --git a/gfxlcd/driver/ssd1306/ssd1306.py b/gfxlcd/driver/ssd1306/ssd1306.py
index 88aff42..4b595a1 100644
--- a/gfxlcd/driver/ssd1306/ssd1306.py
+++ b/gfxlcd/driver/ssd1306/ssd1306.py
@@ -36,7 +36,8 @@ class SSD1306(Page, Chip):
         self.driver.cmd(0xd3)  # set display offset
         self.driver.cmd(0x00)  # not offset
 
-        self.driver.cmd(0xd5)  # set display clock divide ratio/oscillator frequency
+        # set display clock divide ratio/oscillator frequency
+        self.driver.cmd(0xd5)
         self.driver.cmd(0x80)  # set divide ratio
 
         self.driver.cmd(0xd9)  # set pre-charge period