diff --git a/src/grid.py b/src/grid.py
old mode 100644
new mode 100755
--- a/src/grid.py
+++ b/src/grid.py
@@ -60,6 +60,15 @@ class Grid:
         affineIntersection=(rowStart*(boardSize-1-c)+rowEnd*c) / (boardSize-1)
         self.intersections[r][c]=EPoint.fromProjective(transformPoint(affineIntersection.toProjective(),rectiMatrixInv))
 
+  def stoneSizeAt(self,r,c,sizeCoef):
+    intersection=self.intersections[r][c]
+
+    if c>0: width=sizeCoef*(intersection.x-self.intersections[r][c-1].x)
+    else: width=sizeCoef*(self.intersections[r][c+1].x-intersection.x)
+    if r>0: height=sizeCoef*(intersection.y-self.intersections[r-1][c].y)
+    else: height=sizeCoef*(self.intersections[r+1][c].y-intersection.y)
+
+    return (width,height)
 
 
 # from corners import Corners