diff --git a/g2g_gui.py b/g2g_gui.py
index 482fa00..4f64189 100755
--- a/g2g_gui.py
+++ b/g2g_gui.py
@@ -5,6 +5,7 @@
 import sys
 import os
 import string
+import subprocess
 
 from Tkinter import *
 from os import path, access, R_OK, W_OK
@@ -47,6 +48,77 @@
 def floats(s):
   return map(float,string.split(s,','))
 
+def test_forces():
+
+  original_stdout = sys.stdout  # keep a reference to STDOUT
+
+  if Output_name.get():
+    sys.stdout = open(Output_name.get(), 'w')
+
+  if not offset_str.get():
+    default_offset_str()
+  if not matrix_str.get():
+    default_matrix_str()
+  if not speed_str.get():
+    default_speed_str()
+
+
+  offset = floats(offset_str.get())
+  matrix = floats(matrix_str.get())
+  speed = floats(speed_str.get())
+
+  #
+  # main program
+  #
+
+  import graphtec
+  import pic
+  import optimize
+
+#  offset = (5, 1)
+#  matrix = (1, 0, 0, 1)
+
+  g = graphtec.graphtec()
+
+  g.start()
+
+  g.set(offset=offset, matrix=matrix)
+  g.set(speed=speed)
+
+  for i in range(0, 6):
+    for j in range(0, 5):
+      g.set(force=1 + j + 5 * i)
+      tx = 0.5 * j
+      ty = 0.5 * i
+      g.closed_path([(tx, ty), (tx + 0.3, ty), (tx + 0.3, ty + 0.3), (tx, ty + 0.3)])
+
+  g.end()
+
+  if Output_name.get():
+    sys.stdout = original_stdout  # restore STDOUT back to its original value
+    tkMessageBox.showinfo("G2G_GUI Message", "File '%s' created" % (Output_name.get()))
+
+
+def show_gerber():
+
+  if not os.path.exists(Gerber_name.get()):
+    get_input_filename()
+  if not os.path.exists(Gerber_name.get()):
+    tkMessageBox.showerror("G2G_GUI ERROR", "The path provided for the input Gerber file is invalid.")
+    return
+
+  head, tail = os.path.split(Gerber_name.get())
+
+  if not os.path.exists(gerbv_path.get()):
+    tkMessageBox.showerror("G2G_GUI ERROR", "The path provided for gerbv is invalid.")
+    return
+
+  if not os.path.exists(pstoedit_path.get()):
+    tkMessageBox.showerror("G2G_GUI ERROR", "The path provided for pstoedit is invalid.")
+    return
+
+  subprocess.Popen([os.path.normpath(gerbv_path.get()), os.path.normpath(Gerber_name.get())])
+
 def main_program():
   #
   # convert file to pic format
@@ -76,7 +148,7 @@ def main_program():
     if not os.path.exists(pstoedit_path.get()):
       tkMessageBox.showerror("G2G_GUI ERROR", "The path provided for pstoedit is invalid.")
       return
-  
+
   if os.name=='nt':
     os.system("echo \"%s\" --export=pdf --output=%s --border=0 \"%s\" > \"%s\"" % (os.path.normpath(gerbv_path.get()),temp_pdf,os.path.normpath(Gerber_name.get()),temp_bat))
     os.system("echo \"%s\" -q -f pic \"%s\" \"%s\" >> \"%s\"" % (os.path.normpath(pstoedit_path.get()),temp_pdf,temp_pic, temp_bat))
@@ -102,7 +174,7 @@ def main_program():
     default_force_str()
   if not cut_mode_str.get():
     default_cut_mode_str()
-    
+
   offset = floats(offset_str.get())
   border = floats(border_str.get())
   matrix = floats(matrix_str.get())
@@ -179,7 +251,7 @@ def Send_to_Cutter():
     if not Output_name.get():
       return
     src=os.path.normpath(Output_name.get())
-    
+
     if not cutter_shared_name_str.get():
       tkMessageBox.showerror("G2G_GUI ERROR", "The name of the cutter (as a shared printer) was not provided.")
       return
@@ -187,7 +259,7 @@ def Send_to_Cutter():
     #if not os.path.exists(cutter_shared_name_str.get()):
     #  tkMessageBox.showerror("G2G_GUI ERROR", "The name of the cutter (as a shared printer) does not exist.")
     #  return
-    
+
     dst=os.path.normpath(cutter_shared_name_str.get())
     if os.name=='nt':
       os.system("copy /B \"%s\" \"%s\"" % (src, dst))
@@ -216,10 +288,10 @@ def get_pstoedit_path():
 
 def default_offset_str():
     offset_str.set("4.0,0.5")
-    
+
 def default_border_str():
     border_str.set("1,1")
-    
+
 def default_matrix_str():
     matrix_str.set("1,0,0,1")
 
@@ -228,7 +300,7 @@ def default_speed_str():
 
 def default_force_str():
     force_str.set("8,30")
-    
+
 def default_cut_mode_str():
     cut_mode_str.set("0")
 
@@ -279,10 +351,13 @@ def default_cut_mode_str():
   Label(top, text="Cutter Device Name").grid(row=11, column=0, sticky=W)
 Entry(top, bd =1, width=60, textvariable=cutter_shared_name_str).grid(row=11, column=1, sticky=E)
 
-Tkinter.Button(top, width=40, text = "Create Graphtec File", command = main_program).grid(row=12, column=1)
-Tkinter.Button(top, width=40, text = "Send Graphtec File to Silhouette Cutter", command = Send_to_Cutter).grid(row=13, column=1)
-Tkinter.Button(top, width=40, text = "Save Configuration", command = Save_Configuration).grid(row=14, column=1)
-Tkinter.Button(top, width=40, text = "Exit", command = Just_Exit).grid(row=15, column=1)
+Tkinter.Button(top, width=40, text="Show Gerber in Gerbv", command=show_gerber).grid(row=12, column=1)
+Tkinter.Button(top, width=40, text="Create Graphtec File from Input", command=main_program).grid(row=13, column=1)
+Tkinter.Button(top, width=40, text="Send Graphtec File to Silhouette Cutter", command=Send_to_Cutter).grid(row=14, column=1)
+Tkinter.Button(top, width=40, text="Save Configuration", command=Save_Configuration).grid(row=15, column=1)
+Tkinter.Button(top, width=40, text="Exit", command=Just_Exit).grid(row=16, column=1)
+Tkinter.Button(top, width=40, text="Create test_forces Graphtec file", command=test_forces).grid(row=17, column=1)
+
 
 if path.isfile(CONFPATH) and access(CONFPATH, R_OK):
     f = open(CONFPATH,'r')