diff --git a/tools/extent.py b/tools/extent.py
deleted file mode 100755
index 5df7f0f..0000000
--- a/tools/extent.py
+++ /dev/null
@@ -1,103 +0,0 @@
-#!/usr/bin/env python
-import sys
-INF = sys.maxint
-
-
-##  Rect
-##
-class Rect:
-  
-  def __init__(self, x=-INF, y=-INF, width=None, height=None):
-    self.x0 = x
-    self.y0 = y
-    if width == None:
-      self.x1 = INF
-    else:      
-      self.x1 = x+width
-    if height == None:
-      self.y1 = INF
-    else:
-      self.y1 = y+height
-    return
-
-  def __repr__(self):
-    return '<Rect: (%d,%d) (%dx%d)>' % (self.x0, self.y0, self.x1-self.x0, self.y1-self.y0)
-
-  def overlap(self, rect):
-    return not (rect.x1 <= self.x0 or self.x1 <= rect.x0 or
-                rect.y1 <= self.y0 or self.y1 <= rect.y0)
-
-
-##  ExtGrid
-##
-class ExtGrid:
-  
-  def __init__(self, gridsize):
-    self.gridsize = gridsize
-    self.gridy = {}
-    return
-
-  def __repr__(self):
-    return '<ExtGrid(size=%d): %r>' % (self.gridsize, self.gridy)
-  
-  def cells(self, x0, x1):
-    i = int(x0 / self.gridsize)
-    x = i * self.gridsize
-    while x < x1:
-      yield i
-      x += self.gridsize
-      i += 1
-    return
-  
-  def add(self, rect, obj):
-    if isinstance(rect, tuple): rect = Rect(*rect)
-    xcells = list(self.cells(rect.x0, rect.x1))
-    for y in self.cells(rect.y0, rect.y1):
-      if y not in self.gridy:
-        gridx = {}
-        self.gridy[y] = gridx
-      else:
-        gridx = self.gridy[y]
-      for x in xcells:
-        assert isinstance(gridx, dict), gridx
-        if x not in gridx:
-          objs = []
-          gridx[x] = objs
-        else:
-          objs = gridx[x]
-        objs.append((rect, obj))
-        assert isinstance(gridx, dict), gridx
-    return
-  
-  def get(self, rect):
-    if isinstance(rect, tuple): rect = Rect(*rect)
-    objs = set()
-    xcells = list(self.cells(rect.x0, rect.x1))
-    for y in self.cells(rect.y0, rect.y1):
-      if y not in self.gridy: continue
-      gridx = self.gridy[y]
-      for x in xcells:
-        if x not in gridx: continue
-        objs.update( obj for (r,obj) in gridx[x] if rect.overlap(r) )
-    return objs
-
-
-if __name__ == '__main__':
-  e = ExtGrid(10)
-  assert list(e.cells(-1, 1)) == [-1,0]
-  assert list(e.cells(0, 1)) == [0]
-  assert list(e.cells(0, 10)) == [0]
-  assert list(e.cells(0, 11)) == [0,1]
-  assert list(e.cells(1, 11)) == [0,1]
-  assert list(e.cells(10, 11)) == [1]
-  assert list(e.cells(0, 20)) == [0,1]
-  assert list(e.cells(10, 20)) == [1]
-  assert list(e.cells(1,21)) == [0,1,2]
-  assert list(e.cells(11,21)) == [1,2]
-  e.add((0,0,10,10), 'a')
-  e.add((10,10,10,10), 'b')
-  e.add((5,5,5,10), 'c')
-  assert sorted(e.get((0,0,1,1))) == ['a']
-  assert sorted(e.get((10,10,1,1))) == ['b']
-  assert sorted(e.get((5,10,10,10))) == ['b','c']
-  assert sorted(e.get((5,5,10,10))) == ['a','b','c']