diff --git a/util/transform.py b/util/transform.py
index a333ad1..8736bd9 100644
--- a/util/transform.py
+++ b/util/transform.py
@@ -52,18 +52,31 @@ def transform_bounce(
 def transform_oscillate(
     bounds: pg.Rect,
     period: int,
-    initial_pos: XYCoord = (-1, -1),
+    initial_pos: XYCoord = (0, 0),
+    auto_period: int = 0,
 ) -> PositionGenerator:
-    pos_x = float(initial_pos[0] if initial_pos[0] > 0 else bounds.left)
-    pos_y = float(initial_pos[1] if initial_pos[1] > 0 else bounds.top)
+    pos_x = float(initial_pos[0])
+    pos_y = float(initial_pos[1])
     direction = "+"
 
+    last_period = 0
+
     while True:
-        (size_x, size_y), _ = yield (int(pos_x), int(pos_y))
+        (size_x, size_y), is_beat = yield (
+            int(pos_x + bounds.left),
+            int(pos_y + bounds.top),
+        )
 
         range_x = bounds.width - size_x
         range_y = bounds.height - size_y
 
+        if auto_period:
+            if is_beat:
+                period = last_period * auto_period
+                last_period = 0
+            else:
+                last_period += 1
+
         inc_x = range_x / period
         inc_y = range_y / period