diff --git a/agent.py b/agent.py
index cb160af..4a5f67e 100644
--- a/agent.py
+++ b/agent.py
@@ -35,7 +35,8 @@ def __init__(self, env, x = 0, y = 0, metabolism = 4, vision = 6, endowment = 25
     def getEnv(self):
         return self.env
     
-    def setLocation(self, (x, y)):
+    def setLocation(self, t):
+        (x, y) = t
         self.x = x
         self.y = y
 
@@ -81,7 +82,8 @@ def getSexe(self):
     def setFertility(self, fertility):
         self.fertility = fertility
         
-    def setTags(self, (tags, tagsLength)):
+    def setTags(self, t):
+        (tags, tagsLength) = t
         self.tags = tags
         self.tagsLength = tagsLength
         self.tribe = round(float(bin(tags).count('1')) / float(tagsLength))
@@ -211,7 +213,8 @@ def findFreeLocationAround(self, x, y):
         return None
     
     # Cross-over offspring from two parents: parent1 and parent2
-    def createChild(self, parent, (x, y)):
+    def createChild(self, parent, t):
+        (x, y) = t
         # cross-over parents genetics
         genitors = [self, parent]
         metabolism = genitors[random.randint(0,1)].metabolism
diff --git a/environment.py b/environment.py
index 5773128..4fb664c 100644
--- a/environment.py
+++ b/environment.py
@@ -12,25 +12,30 @@ class Environment:
     classdocs
     '''
     
-    def __init__(self, (width, height)):
+    def __init__(self, t):
         '''
         Constructor
         '''
+        (width, height) = t
         self.gridWidth = width
         self.gridHeight = height
         self.grid = [[[0, 0, None] for i in range(width)] for j in range(height)]
 
-    def setCapacity(self, (i, j), value):
+    def setCapacity(self, t, value):
+        (i, j) = t
         self.grid[i][j][0] = value
     
-    def getCapacity(self, (i, j)):
+    def getCapacity(self, t):
+        (i, j) = t
         return int(self.grid[i][j][0])
 
-    def decCapacity(self, (i,j), value):
+    def decCapacity(self, t, value):
+        (i, j) = t
         self.grid[i][j][0] = max(0, self.grid[i][j][0] - value)
 
-    def addFoodSite(self, (si, sj, r), maxCapacity):
+    def addFoodSite(self, t, maxCapacity):
         # calculate radial dispersion of capacity from maxCapacity to 0
+        (si, sj, r) = t
         distance = lambda di, dj : sqrt(di*di + dj*dj)
         D = distance(max(si, self.gridWidth - si), max(sj, self.gridHeight - sj)) * (r/float(self.gridWidth))
         for i,j in product(range(self.gridWidth), range(self.gridHeight)):
@@ -43,8 +48,9 @@ def grow(self, alpha):
         for i,j in product(range(self.gridWidth), range(self.gridHeight)):
             self.grid[i][j][0] = min(self.grid[i][j][0] + alpha, self.grid[i][j][1])
 
-    def growRegion(self, (imin, jmin, imax, jmax), alpha):
+    def growRegion(self, t, alpha):
         # grow  region to maxCapacity with alpha
+        (imin, jmin, imax, jmax) = t
         imin = max(imin, 0)
         jmin = max(jmin, 0)
         imax = min(imax + 1, self.gridWidth)
@@ -53,19 +59,24 @@ def growRegion(self, (imin, jmin, imax, jmax), alpha):
             for i in range (imin, imax):
                 self.grid[i][j][0] = min(self.grid[i][j][0] + alpha, self.grid[i][j][1])
 
-    def setAgent(self, (i, j), agent):
+    def setAgent(self, t, agent):
+        (i, j) = t
         self.grid[i][j][2] = agent
 
-    def getAgent(self, (i, j)):
+    def getAgent(self, t):
+        (i, j) = t
         return self.grid[i][j][2]
 
-    def isLocationValid(self, (i, j)):
+    def isLocationValid(self, t):
+        (i, j) = t
         return (i >= 0 and i < self.gridWidth and  j >= 0 and j < self.gridHeight)
     
-    def isLocationFree(self, (i, j)):
+    def isLocationFree(self, t):
+        (i, j) = t
         return (self.grid[i][j][2] == None)
         
-    def getRandomFreeLocation(self,(xmin, xmax, ymin, ymax)):
+    def getRandomFreeLocation(self, t):
+        (xmin, xmax, ymin, ymax) = t
         # build a list of free locations i.e. where env.getAgent(x,y) == None
         # we don't use a global list and we re-build the list each time 
         # because init a new agent is much less frequent than updating agent's position (that would require append / remove to the global list)
diff --git a/sugarscape.py b/sugarscape.py
index bd25e16..1b4f591 100644
--- a/sugarscape.py
+++ b/sugarscape.py
@@ -302,7 +302,7 @@ def removeAgent(self, agent):
             if initAgent(agent, tags, self.findDistribution(tags)):
                 self.env.setAgent(agent.getLocation(), agent)
             else:
-                print "initAgent failed!"
+                print("initAgent failed!")
                 self.agents.remove(agent)
         else:
             self.agents.remove(agent)
@@ -478,7 +478,7 @@ def mainLoop(self):
                 
             # display infos
             if update:
-                print "Iteration = ", self.iteration, "; fps = ", framerate, "; Seasons (N,S) = ", self.season, "; Population = ", len(self.agents), " -  press F12 to pause."
+                print("Iteration = ", self.iteration, "; fps = ", framerate, "; Seasons (N,S) = ", self.season, "; Population = ", len(self.agents), " -  press F12 to pause.")
 
 ''' 
 Main 
diff --git a/wdgAgent.py b/wdgAgent.py
index c92993e..c0ff80b 100644
--- a/wdgAgent.py
+++ b/wdgAgent.py
@@ -3,7 +3,7 @@
 
 @author: rv
 '''
-from Tkinter import *
+from tkinter import *
 
 class WdgAgent():
     '''
diff --git a/wdgPopulation.py b/wdgPopulation.py
index 1f3653f..f39c398 100644
--- a/wdgPopulation.py
+++ b/wdgPopulation.py
@@ -4,7 +4,7 @@
 @author: rv
 '''
 
-from Tkinter import *
+from tkinter import *
 
 class WdgPopulation():
     '''
diff --git a/wdgWealth.py b/wdgWealth.py
index 9bb0ba0..39fff2a 100644
--- a/wdgWealth.py
+++ b/wdgWealth.py
@@ -3,7 +3,7 @@
 
 @author: rv
 '''
-from Tkinter import *
+from tkinter import *
 
 class WdgWealth():
     '''