diff --git a/WIP/WIP: 154-cycpattern_check.py b/WIP/WIP: 154-cycpattern_check.py
index e69de29..8387dc6 100644
--- a/WIP/WIP: 154-cycpattern_check.py	
+++ b/WIP/WIP: 154-cycpattern_check.py	
@@ -0,0 +1,99 @@
+from typing import List
+from nagini_contracts.contracts import *
+
+@Pure
+def IsSubstring(s : List[int], sub : List[int], n : int) -> bool :
+    Requires(Acc(list_pred(s)))
+    Requires(Acc(list_pred(sub)))
+    return ((len(s)) >= (len(sub))) and (Exists(int, lambda d_0_i_:
+        (((0) <= (d_0_i_)) and ((d_0_i_) < 1 + ((len(s)) - (len(sub))))) and (
+            Forall(int, lambda y: (Implies(y >= 0 and y < len(sub), sub[(n + y) % len(sub)] == s[d_0_i_ + y]), [[sub[(n + y) % len(sub)] == s[d_0_i_ + y]]])))))
+
+# def IsSubstringFunc(s : List[int], sub : List[int], n : int) -> bool :
+#     Requires(Acc(list_pred(s)))
+#     Requires(Acc(list_pred(sub)))
+#     Ensures(Acc(list_pred(s)))
+#     Ensures(Acc(list_pred(sub)))
+#     Ensures(Implies(Result(), len(s) >= len(sub)))
+#     # Ensures(Result() == (((len(s)) >= (len(sub))) and (Exists(int, lambda d_0_i_:
+#     #     (((0) <= (d_0_i_)) and ((d_0_i_) < 1 + ((len(s)) - (len(sub))))) and (
+#     #         Forall(int, lambda y: (Implies(y >= 0 and y < len(sub), sub[(n + y) % len(sub)] == s[d_0_i_ + y]), [[sub[(n + y) % len(sub)] == s[d_0_i_ + y]]])))))))
+    
+#     if (len(s) < len(sub)):
+#         return False
+    
+#     i = 0 # type : int
+#     while i <= len(s) - len(sub):
+#         Invariant(Acc(list_pred(s), 1/2))
+#         Invariant(Acc(list_pred(sub), 1/2))
+#         Invariant(((0) <= (i)) and ((i) <= 1 + ((len(s)) - (len(sub)))))
+#         Invariant(len(s) >= len(sub))
+#         # Invariant(Forall(int, lambda d_0_i: 
+#         #     (Implies(d_0_i >= 0 and d_0_i < i, 
+#         #         Exists(int, lambda y: y >= 0 and y < len(sub) and sub[(n + y) % len(sub)] != s[d_0_i + y])), 
+#         #             [[Exists(int, lambda y: y >= 0 and y < len(sub) and sub[(n + y) % len(sub)] != s[d_0_i + y])]])))
+        
+#         Assume(Forall(int, lambda d_0_i: 
+#             (Implies(d_0_i >= 0 and d_0_i < i, 
+#                 Exists(int, lambda y: y >= 0 and y < len(sub) and sub[(n + y) % len(sub)] != s[d_0_i + y])), 
+#                 [[Exists(int, lambda y: y >= 0 and y < len(sub) and sub[(n + y) % len(sub)] != s[d_0_i + y])]])))
+#         j = 0 # type : int
+#         fl = True # type : bool
+#         Assert(Forall(int, lambda d_0_i: 
+#             (Implies(d_0_i >= 0 and d_0_i < i, 
+#                 Exists(int, lambda y: y >= 0 and y < len(sub) and sub[(n + y) % len(sub)] != s[d_0_i + y])), 
+#                 [[Exists(int, lambda y: y >= 0 and y < len(sub) and sub[(n + y) % len(sub)] != s[d_0_i + y])]])))  
+#         while j < len(sub):
+#             Invariant(Acc(list_pred(s), 1/2))
+#             Invariant(Acc(list_pred(sub), 1/2))
+#             Invariant(((0) <= (j)) and ((j) <= (len(sub))))
+#             Invariant(((0) <= (i)) and ((i) <= ((len(s)) - (len(sub)))))
+#             Invariant(len(s) >= len(sub))
+#             Invariant(fl)
+#             Invariant(Forall(int, lambda d_0_i: 
+#                 (Implies(d_0_i >= 0 and d_0_i < i, 
+#                     Exists(int, lambda y: y >= 0 and y < len(sub) and sub[(n + y) % len(sub)] != s[d_0_i + y])), 
+#                     [[Exists(int, lambda y: y >= 0 and y < len(sub) and sub[(n + y) % len(sub)] != s[d_0_i + y])]])))  
+#             Invariant(Implies(fl, Forall(int, lambda y: (Implies(y >= 0 and y < j, sub[(n + y) % len(sub)] == s[i + y]), [[sub[(n + y) % len(sub)] == s[i + y]]]))))
+#             if sub[(n + j) % len(sub)] != s[i + j]:
+#                 fl = False
+#                 Assert(fl == (j == len(sub)))
+#                 break
+#             j = j + 1
+
+#         Assert(fl == (j == len(sub)))
+#         if j == len(sub):
+#             Assert(IsSubstring(s, sub, n))
+#             return True
+#         Assert(Exists(int, lambda y: y >= 0 and y < len(sub) and sub[(n + y) % len(sub)] != s[i + y]))
+#         Assert(Forall(int, lambda d_0_i: 
+#             (Implies(d_0_i >= 0 and d_0_i <= i, 
+#                 Exists(int, lambda y: y >= 0 and y < len(sub) and sub[(n + y) % len(sub)] != s[d_0_i + y])), 
+#                 [[Exists(int, lambda y: y >= 0 and y < len(sub) and sub[(n + y) % len(sub)] != s[d_0_i + y])]])))
+#         i = i + 1
+#     return False
+
+# def CycpatternCheck(word : List[int], pattern : List[int]) -> bool:
+#     Requires(Acc(list_pred(word)))
+#     Requires(Acc(list_pred(pattern)))
+#     Ensures(Acc(list_pred(word)))
+#     Ensures(Acc(list_pred(pattern)))
+#     Ensures(not (Result()) or (Exists(int, lambda d_1_i_:
+#         (((0) <= (d_1_i_)) and ((d_1_i_) <= (len(pattern)))) and (IsSubstring(word, pattern, d_1_i_)))))
+#     Ensures(not (not(Result())) or (Forall(int, lambda d_2_i_:
+#         not (((0) <= (d_2_i_)) and ((d_2_i_) <= (len(pattern)))) or (not(IsSubstring(word, pattern, d_2_i_))))))
+#     result = False # type : bool
+#     d_3_i_ = int(0) # type : int
+#     d_3_i_ = 0
+#     while (d_3_i_) <= (len(pattern)):
+#         Invariant(Acc(list_pred(word)))
+#         Invariant(Acc(list_pred(pattern)))
+#         Invariant(((0) <= (d_3_i_)) and ((d_3_i_) <= ((len(pattern)) + (1))))
+#         Invariant(Forall(int, lambda d_4_j_:
+#             (Implies(((0) <= (d_4_j_)) and ((d_4_j_) < (d_3_i_)), not(IsSubstring(word, pattern, d_4_j_))), [[IsSubstring(word, pattern, d_4_j_)]])))
+#         if IsSubstring(word, pattern, d_3_i_):
+#             result = True
+#             return result
+#         d_3_i_ = (d_3_i_) + (1)
+#     result = False
+#     return result
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