diff --git a/py/Pipfile b/py/Pipfile
index be22fdc..433219a 100644
--- a/py/Pipfile
+++ b/py/Pipfile
@@ -8,6 +8,6 @@
 
 [packages]
 requests = "*"
-
+python-constraint = "*"
 [requires]
 python_version = "3.7"

diff --git a/py/Pipfile b/py/Pipfile
index be22fdc..433219a 100644
--- a/py/Pipfile
+++ b/py/Pipfile
@@ -8,6 +8,6 @@
 
 [packages]
 requests = "*"
-
+python-constraint = "*"
 [requires]
 python_version = "3.7"
diff --git a/py/Pipfile.lock b/py/Pipfile.lock
index 7705726..75fc268 100644
--- a/py/Pipfile.lock
+++ b/py/Pipfile.lock
@@ -1,7 +1,7 @@
 {
     "_meta": {
         "hash": {
-            "sha256": "d6b06c358e3a82c0f18eeb9729511dfcbdfe6593ec78842704abe5a445182b84"
+            "sha256": "8b1fcdb84828bfaf54abbf47069942063faff55fa75532e0ce444d9100936859"
         },
         "pipfile-spec": 6,
         "requires": {
@@ -37,6 +37,13 @@
             ],
             "version": "==2.8"
         },
+        "python-constraint": {
+            "hashes": [
+                "sha256:501d6f17afe0032dfc6ea6c0f8acc12e44f992733f00e8538961031ef27ccb8e"
+            ],
+            "index": "pypi",
+            "version": "==1.4.0"
+        },
         "requests": {
             "hashes": [
                 "sha256:502a824f31acdacb3a35b6690b5fbf0bc41d63a24a45c4004352b0242707598e",
@@ -127,9 +134,9 @@
         },
         "wrapt": {
             "hashes": [
-                "sha256:d4d560d479f2c21e1b5443bbd15fe7ec4b37fe7e53d335d3b9b0a7b1226fe3c6"
+                "sha256:4aea003270831cceb8a90ff27c4031da6ead7ec1886023b80ce0dfe0adf61533"
             ],
-            "version": "==1.10.11"
+            "version": "==1.11.1"
         }
     }
 }

diff --git a/py/Pipfile b/py/Pipfile
index be22fdc..433219a 100644
--- a/py/Pipfile
+++ b/py/Pipfile
@@ -8,6 +8,6 @@
 
 [packages]
 requests = "*"
-
+python-constraint = "*"
 [requires]
 python_version = "3.7"
diff --git a/py/Pipfile.lock b/py/Pipfile.lock
index 7705726..75fc268 100644
--- a/py/Pipfile.lock
+++ b/py/Pipfile.lock
@@ -1,7 +1,7 @@
 {
     "_meta": {
         "hash": {
-            "sha256": "d6b06c358e3a82c0f18eeb9729511dfcbdfe6593ec78842704abe5a445182b84"
+            "sha256": "8b1fcdb84828bfaf54abbf47069942063faff55fa75532e0ce444d9100936859"
         },
         "pipfile-spec": 6,
         "requires": {
@@ -37,6 +37,13 @@
             ],
             "version": "==2.8"
         },
+        "python-constraint": {
+            "hashes": [
+                "sha256:501d6f17afe0032dfc6ea6c0f8acc12e44f992733f00e8538961031ef27ccb8e"
+            ],
+            "index": "pypi",
+            "version": "==1.4.0"
+        },
         "requests": {
             "hashes": [
                 "sha256:502a824f31acdacb3a35b6690b5fbf0bc41d63a24a45c4004352b0242707598e",
@@ -127,9 +134,9 @@
         },
         "wrapt": {
             "hashes": [
-                "sha256:d4d560d479f2c21e1b5443bbd15fe7ec4b37fe7e53d335d3b9b0a7b1226fe3c6"
+                "sha256:4aea003270831cceb8a90ff27c4031da6ead7ec1886023b80ce0dfe0adf61533"
             ],
-            "version": "==1.10.11"
+            "version": "==1.11.1"
         }
     }
 }
diff --git a/py/README.md b/py/README.md
index daf6548..1e7491b 100644
--- a/py/README.md
+++ b/py/README.md
@@ -6,5 +6,5 @@
 
 ## Skewed Random Generator
 
-## Random Generator
+## Even Random Generator
 

diff --git a/py/Pipfile b/py/Pipfile
index be22fdc..433219a 100644
--- a/py/Pipfile
+++ b/py/Pipfile
@@ -8,6 +8,6 @@
 
 [packages]
 requests = "*"
-
+python-constraint = "*"
 [requires]
 python_version = "3.7"
diff --git a/py/Pipfile.lock b/py/Pipfile.lock
index 7705726..75fc268 100644
--- a/py/Pipfile.lock
+++ b/py/Pipfile.lock
@@ -1,7 +1,7 @@
 {
     "_meta": {
         "hash": {
-            "sha256": "d6b06c358e3a82c0f18eeb9729511dfcbdfe6593ec78842704abe5a445182b84"
+            "sha256": "8b1fcdb84828bfaf54abbf47069942063faff55fa75532e0ce444d9100936859"
         },
         "pipfile-spec": 6,
         "requires": {
@@ -37,6 +37,13 @@
             ],
             "version": "==2.8"
         },
+        "python-constraint": {
+            "hashes": [
+                "sha256:501d6f17afe0032dfc6ea6c0f8acc12e44f992733f00e8538961031ef27ccb8e"
+            ],
+            "index": "pypi",
+            "version": "==1.4.0"
+        },
         "requests": {
             "hashes": [
                 "sha256:502a824f31acdacb3a35b6690b5fbf0bc41d63a24a45c4004352b0242707598e",
@@ -127,9 +134,9 @@
         },
         "wrapt": {
             "hashes": [
-                "sha256:d4d560d479f2c21e1b5443bbd15fe7ec4b37fe7e53d335d3b9b0a7b1226fe3c6"
+                "sha256:4aea003270831cceb8a90ff27c4031da6ead7ec1886023b80ce0dfe0adf61533"
             ],
-            "version": "==1.10.11"
+            "version": "==1.11.1"
         }
     }
 }
diff --git a/py/README.md b/py/README.md
index daf6548..1e7491b 100644
--- a/py/README.md
+++ b/py/README.md
@@ -6,5 +6,5 @@
 
 ## Skewed Random Generator
 
-## Random Generator
+## Even Random Generator
 
diff --git a/py/even_random_generator.py b/py/even_random_generator.py
index ffa3c8a..1775aaa 100644
--- a/py/even_random_generator.py
+++ b/py/even_random_generator.py
@@ -1,3 +1,4 @@
+from constraint import *
 
 class EvenRandomGenerator:
     """Generate even random sequences according to a predefined TL ration (Ralph, 2014)"""
@@ -25,17 +26,35 @@
 
         return seq
 
-    def _optimize_sequence(self, seq):
-        """Optimize a sequence based on a desired tl ratio"""
-        # TODO optimize sequence according to the fitness function w/ Branch&Bound or evolutionary algorithms.
+    def _optimize_sequence(self, seq, tl_ratio):
+        """Optimize a sequence to match a desired tl ratio"""
+
+        p = Problem()
+
+        # TODO add all possible values for seq (its domain)
+        p.addVariable("seq", [seq])
+
+        p.addConstraint(lambda s: self.calculate_tl_ratio(s) - tl_ratio < 0.05)
+
         return seq
 
     @staticmethod
     def calculate_tl_ratio(seq):
         """Calculates the T:L ratio of a sequence."""
-        # TODO
         targets = 0
+        lures = 0
         for index, item in seq:
             if item == seq[index-2]:
                 targets += 1
-        return 1.0
+            elif item == seq[index-1] or item == seq[index-3]:
+                lures += 1
+        # avoid division by zero
+        if lures == 0:
+            lures = 1
+        return targets/lures
+
+
+if __name__ == '__main__':
+    generator = EvenRandomGenerator(['a','b','c'])
+    generated_seq = generator.generate()
+    print('Even Random Sequence: %s' % ''.join(generated_seq))