diff --git a/pigeon_magnet_solver/helpers.py b/pigeon_magnet_solver/helpers.py
new file mode 100644
index 0000000..d868189
--- /dev/null
+++ b/pigeon_magnet_solver/helpers.py
@@ -0,0 +1,36 @@
+def _rotate_r(__s: str) -> str:
+    return __s[-1] + __s[0:-1]
+
+
+def _valid_rotate(__s: str, __c: str) -> bool:
+    for sc, cc in zip(__s, __c):
+        # can never rotate a "1" onto an "x"
+        if sc == "x" and cc == "1":
+            return False
+
+    return True
+
+
+def _fix_exes(__s: str, __c: str) -> str:
+    result = ""
+
+    for sc, cc in zip(__s, __c):
+        if sc == "x":
+            result += "x"
+
+        elif cc == "x":
+            result += "0"
+
+        else:
+            result += cc
+
+    return result
+
+
+def rotate_r(__s: str) -> str:
+    result = _rotate_r(__s)
+
+    while not _valid_rotate(__s, result):
+        result = _rotate_r(result)
+
+    return _fix_exes(__s, result)
diff --git a/tests/test_helpers.py b/tests/test_helpers.py
new file mode 100644
index 0000000..8fe75c9
--- /dev/null
+++ b/tests/test_helpers.py
@@ -0,0 +1,17 @@
+from pigeon_magnet_solver import helpers
+
+
+def test_rotate_r():
+    assert helpers._rotate_r("1x01") == "11x0"
+    assert helpers._rotate_r("11x0") == "011x"
+    assert helpers._rotate_r("011x") == "x011"
+    assert helpers._rotate_r("x011") == "1x01"
+
+    assert helpers._valid_rotate("1x01", "11x0") is False
+    assert helpers._valid_rotate("1x01", "011x") is False
+    assert helpers._valid_rotate("1x01", "x011") is True
+    assert helpers._valid_rotate("1x01", "1x01") is True
+
+    assert helpers._fix_exes("1x01", "x011") == "0x11"
+
+    assert helpers.rotate_r("1x01") == "0x11"