diff --git a/exp/color_sampler.py b/exp/color_sampler.py
--- a/exp/color_sampler.py
+++ b/exp/color_sampler.py
@@ -1,9 +1,15 @@
+import sys
+sys.path.append("../src")
+
 import os
 import tkinter as tk
+from tkinter import LEFT,X,N,S,E,W
 from colorsys import rgb_to_hsv
 
 from PIL import Image,ImageTk
 
+from analyzer.corners import Corners
+
 
 class Sampler:
 	def __init__(self):
@@ -15,16 +21,32 @@ class Sampler:
 		self.photo=None
 
 		self.letter="_"
+		self.hsv=(0,0,0)
+		self.pos=(0,0)
+		self.corners=Corners()
+
+		self._createGUI()
 
 	def sample(self,e):
-		(r,g,b)=(x/255 for x in self.img.getpixel((e.x,e.y)))
+		try:
+			(r,g,b)=(x/255 for x in self.img.getpixel((e.x,e.y)))
+		except IndexError:
+			return
+
 		(h,s,v)=map(lambda x: round(x,3), rgb_to_hsv(r,g,b))
-		print("\t".join(map(str, (self.filenames[self.k],e.x,e.y,self.letter,h,s,v))))
+		self.hsv=(h,s,v)
+		self.pos=(e.x,e.y)
+		self.posLabel.configure(text="({0},{1})".format(e.x,e.y))
+		self.colorLabel.configure(text="HSV: ({0}, {1}, {2})".format(round(h*360),s,v))
+
+	def printSample(self):
+		print("\t".join(map(str, (self.filenames[self.k],*self.pos,self.letter,*self.hsv))))
 
 	def showImage(self):
 		self.img=Image.open(os.path.join(self.dirname,self.filenames[self.k]))
 		(w,h)=self.img.size
 		self.photo=ImageTk.PhotoImage(self.img)
+		self.canvas.delete("all")
 		self.canvas.create_image(0,0,image=self.photo,anchor="nw")
 		self.canvas.configure(width=w,height=h)
 
@@ -35,16 +57,28 @@ class Sampler:
 
 	def setLetter(self,c):
 		self.letter=c
+		self.letterLabel.configure(text="Letter: {0}".format(c))
 
-	def createGUI(self):
+	def addCorner(self,e):
+		self.corners.add(e.x,e.y)
+		self._markCorners()
+
+	def _createGUI(self):
 		root=tk.Tk()
 		frame=tk.Frame(root)
-		frame.pack()
+		frame.grid(column=0,row=0,sticky=(N,S,E,W))
+
 		self.canvas=tk.Canvas(frame)
-		self.canvas.pack()
+		self.canvas.grid(row=1,column=0)
+
+		bar=self._createBar(frame)
+		bar.grid(row=2,column=0,sticky=(E,W))
+
 		self.showImage()
 
-		self.canvas.bind('<1>',self.sample)
+		self.canvas.bind('<1>',lambda e: self.printSample())
+		self.canvas.bind('<3>',self.addCorner)
+		self.canvas.bind("<Motion>",self.sample)
 		root.bind("<Left>",lambda e: self.switchImage(-1))
 		root.bind("<Right>",lambda e: self.switchImage(1))
 		root.bind("<b>",lambda e: self.setLetter("b"))
@@ -53,6 +87,28 @@ class Sampler:
 
 		root.mainloop()
 
+	def _createBar(self,frame):
+		bar=tk.Frame(frame,height=20,borderwidth=1,relief="sunken")
+		self.letterLabel=tk.Label(bar,width=8,text="Letter: _")
+		self.letterLabel.pack(side=LEFT)
+		self.posLabel=tk.Label(bar,width=16,text="(,)")
+		self.posLabel.pack(side=LEFT)
+		self.colorLabel=tk.Label(bar,width=20,text="HSV: (,,)")
+		self.colorLabel.pack(side=LEFT)
+
+		return bar
+
+	def _markCorners(self):
+		self.canvas.delete("mark")
+		for c in self.corners:
+			(x,y)=(c.x,c.y)
+			self.canvas.create_oval(x-2,y-2,x+2,y+2,fill="#00ff00",tags="mark")
+		if self.corners.canonizeOrder():
+			(a,b,c,d)=self.corners
+			self.canvas.create_line(a.x,a.y,b.x,b.y,fill="#00ff00",tags="mark")
+			self.canvas.create_line(b.x,b.y,c.x,c.y,fill="#00ff00",tags="mark")
+			self.canvas.create_line(c.x,c.y,d.x,d.y,fill="#00ff00",tags="mark")
+			self.canvas.create_line(d.x,d.y,a.x,a.y,fill="#00ff00",tags="mark")
+
 
 s=Sampler()
-s.createGUI()