diff --git a/evolve-die-repeat/game_manager.gd b/evolve-die-repeat/game_manager.gd
index 51c239f..490f2ca 100644
--- a/evolve-die-repeat/game_manager.gd
+++ b/evolve-die-repeat/game_manager.gd
@@ -4,8 +4,37 @@ var screen_size = Vector2(1920.0, 1080.0)  # Default screen size (this is a floa
 var viewport_size
 @onready var extent: Rect2 = get_viewport().get_visible_rect()
 
+# utils.
+var rng = RandomNumberGenerator.new()
+var eps: float = 1e-4
+
+# A world "current"
+# polar
+var flow_dir: float  # [0, 2pi)
+var flow_mag: float  # [0, 1]
+# cartesian
+var flow_x: float
+var flow_y: float
+# Swap period
+var flowT: float = 10
+
+# A game timer
+var t: float = 0.0
+
+
 func _ready() -> void:
 	viewport_size = get_viewport().get_visible_rect().size
+	
+	# initial world current
+	get_new_flow()
+
+func _physics_process(delta: float) -> void:
+	t += delta
+	
+	# Flow current change
+	if abs(fmod(t, flowT)) < eps:
+		get_new_flow()
+	
 
 # TODO: This needs to be called from a script inheriting a CharacterBody2D (e.g. the player)
 # Alternative would be to pass the player reference to this script (which might be better?)
@@ -22,3 +51,12 @@ func get_boundaried_position(position):
 	position.x = wrapf(position.x, 0, screen_size.x)
 	position.y = wrapf(position.y, 0, screen_size.y)
 	return position
+	
+func get_new_flow():
+	flow_dir = rng.randf()*2*PI
+	flow_mag = rng.randf()
+	
+	flow_x = flow_mag * cos(flow_dir)
+	flow_y = flow_mag * sin(flow_dir)
+	
+	
diff --git a/evolve-die-repeat/main_menu.tscn b/evolve-die-repeat/main_menu.tscn
index dbcbb34..8dbae52 100644
--- a/evolve-die-repeat/main_menu.tscn
+++ b/evolve-die-repeat/main_menu.tscn
@@ -1,11 +1,11 @@
-[gd_scene load_steps=3 format=3 uid="uid://drgv154ei1vrl"]
+[gd_scene format=3 uid="uid://drgv154ei1vrl"]
 
 [ext_resource type="Script" uid="uid://dxc66bci2ivrj" path="res://main_menu.gd" id="1_06t4h"]
 
 [sub_resource type="LabelSettings" id="LabelSettings_rhts7"]
 font_size = 64
 
-[node name="MainMenu" type="Control"]
+[node name="MainMenu" type="Control" unique_id=369570860]
 layout_mode = 3
 anchors_preset = 15
 anchor_right = 1.0
@@ -14,7 +14,7 @@ grow_horizontal = 2
 grow_vertical = 2
 script = ExtResource("1_06t4h")
 
-[node name="PlayButton" type="Button" parent="."]
+[node name="PlayButton" type="Button" parent="." unique_id=1831335357]
 layout_mode = 0
 offset_left = 448.0
 offset_top = 256.0
@@ -22,7 +22,7 @@ offset_right = 768.0
 offset_bottom = 314.0
 text = "Play"
 
-[node name="MainMenuText" type="Label" parent="."]
+[node name="MainMenuText" type="Label" parent="." unique_id=1324657553]
 layout_mode = 0
 offset_left = 320.0
 offset_top = 32.0
diff --git a/evolve-die-repeat/molecular/food/abstract_food.gd b/evolve-die-repeat/molecular/food/abstract_food.gd
index e01a4e9..2d5e15d 100644
--- a/evolve-die-repeat/molecular/food/abstract_food.gd
+++ b/evolve-die-repeat/molecular/food/abstract_food.gd
@@ -5,11 +5,17 @@ extends Area2D
 @export var val: int = 1
 @export var food_name: String = "Food"
 
+@export var flow_carry_speed: float = 10.0
+
 signal consumed
 
 func _ready() -> void:
 	pass
 
+func _physics_process(delta: float) -> void:
+	var dpos = Vector2(GameManager.flow_x, GameManager.flow_y) * delta * flow_carry_speed
+	position += dpos
+
 func _on_body_entered(body: Node2D) -> void:
 	pass
 
diff --git a/evolve-die-repeat/molecular/food/food_mol.gd b/evolve-die-repeat/molecular/food/food_mol.gd
index d19f742..ba8d73d 100644
--- a/evolve-die-repeat/molecular/food/food_mol.gd
+++ b/evolve-die-repeat/molecular/food/food_mol.gd
@@ -1,6 +1,7 @@
 extends AbstractFood
 class_name FoodMolecular
 
+
 func _on_body_entered(body: Node2D) -> void:
 	eat(body)