diff --git a/README.markdown b/README.markdown
index cc43ed9..47b2b8a 100644
--- a/README.markdown
+++ b/README.markdown
@@ -39,6 +39,7 @@ Should be used in order to help future reuse of code :)
 24 - What is the millionth lexicographic permutation of the digits 0, 1, 2, 3, 4, 5, 6, 7, 8 and 9? - too long <br />
 25 - What is the first term in the Fibonacci sequence to contain 1000 digits? - 0.741 <br />
 27 - Find a quadratic formula that produces the maximum number of primes for consecutive values of n. - too long <br />
+28 - What is the sum of both diagonals in a 1001 by 1001 spiral? - < 1 sec <br />
 29 - How many distinct terms are in the sequence generated by ab for 2  a  100 and 2  b  100? - < 1 sec <br />
 30 - Find the sum of all the numbers that can be written as the sum of fifth powers of their digits. - < 3 sec <br />
 34 - Find the sum of all numbers which are equal to the sum of the factorial of their digits. - 30 sec  <br />
@@ -52,7 +53,6 @@ Should be used in order to help future reuse of code :)
 **In progress: **
 
 26 - Find the value of d < 1000 for which 1/d contains the longest recurring cycle. <br />
-28 - What is the sum of both diagonals in a 1001 by 1001 spiral? <br />
 35 - How many circular primes are there below one million? <br />
 39 - If p is the perimeter of a right angle triangle, {a, b, c}, which value, for p <= 1000, has the most solutions? <br />
 
diff --git a/e_28.py b/e_28.py
index 7828518..8fbce55 100644
--- a/e_28.py
+++ b/e_28.py
@@ -17,14 +17,30 @@ It can be verified that the sum of the numbers on the diagonals is 101.
 
 What is the sum of the numbers on the diagonals in a 1001 by 1001 spiral formed in the same way?
 ''' 
-def sum_power():
+def sum_diag(max_lines):
     """
-    Finds
+    Returns the sum of both diagonals of the square of max_lines size
     """
+    dsum = 1 # sum of diagonals
+    cpt = 1 # number of lines processed
+    val = 1 # value of the current place in the square
+    inc = 0 # the increment between number for one line
+    
+    while cpt < max_lines:
+        cpt += 2
+        inc += 2
+        
+        for corner in range(4):
+            val += inc
+            dsum += val
 
-
-    return 1
+    return dsum
 
 if __name__ == '__main__':
-    # The major problem in there is to find the upper limit.  
-    print "Answer : %d " % (sum_power())
+    # The major problem in there is to find the logic
+    #n = 1 gives 1 
+    #n = 3 gives 3, 5, 7, 9 => +2
+    #n = 5 gives 13, 17, 21, 25 => +4
+    #n = 7 gives 31, 37, 43, 49 => +6
+    #n = 9 gives 57, . . .      
+    print "Answer : %d " % (sum_diag(1001))