diff --git a/scripts/inventory/inventory.gd b/scripts/inventory/inventory.gd
index 17faa33..6512556 100644
--- a/scripts/inventory/inventory.gd
+++ b/scripts/inventory/inventory.gd
@@ -13,10 +13,14 @@ func _init() -> void:
 ## Tries to add an item into inventory. Returns not stored stack of item.
 @abstract
 func add(stack : Stack) -> Stack
+@abstract
+func add_from_side(stack : Stack, ang_diff : float) -> Stack
 
 ## Returns if conditions of adding are met
 @abstract
 func can_add() -> bool
+@abstract
+func can_add_from_side(ang_diff : float) -> bool
 
 ## Tries to take first item. Returns null if no items in inventory
 @abstract
diff --git a/scripts/inventory/queue.gd b/scripts/inventory/queue.gd
index 511fc79..45ee8cc 100644
--- a/scripts/inventory/queue.gd
+++ b/scripts/inventory/queue.gd
@@ -44,12 +44,18 @@ func add(stack: Stack) -> Stack:
 			return null
 	return stack
 
+func add_from_side(stack : Stack, _ang_diff : float) -> Stack:
+	return add(stack)
+
 func can_add() -> bool:
 	for i in range(capacity):
 		if internal_array[i].amount == 0:
 			return true
 	return false
 
+func can_add_from_side(_ang_diff : float) -> bool:
+	return can_add()
+
 ## Tries to take first item. Returns null if no items in inventory
 func pop() -> Stack:
 	if internal_array[0].held_item == null:
diff --git a/scripts/inventory/storage.gd b/scripts/inventory/storage.gd
index dd58e21..f1d2dfe 100644
--- a/scripts/inventory/storage.gd
+++ b/scripts/inventory/storage.gd
@@ -48,12 +48,18 @@ func add(stack: Stack) -> Stack:
 			return null
 	return stack
 
+func add_from_side(stack : Stack, _ang_diff : float) -> Stack:
+	return add(stack)
+
 func can_add() -> bool:
 	for i in range(capacity):
 		if internal_array[i].amount == 0:
 			return true
 	return false
 
+func can_add_from_side(_ang_diff : float) -> bool:
+	return can_add()
+
 ## Tries to take first item. Returns null if no items in inventory
 func pop() -> Stack:
 	for i in range(len(internal_array)):
diff --git a/scripts/structures/conveyor.gd b/scripts/structures/conveyor.gd
index 02cf5ef..d851cbc 100644
--- a/scripts/structures/conveyor.gd
+++ b/scripts/structures/conveyor.gd
@@ -20,7 +20,7 @@ func _process(delta: float) -> void:
 	inventory.advance(delta)
 	queue_redraw()
 	var next : Structure = get_next()
-	if next == null or next.inventory.can_add_from_side(Globals.facing_difference(next.facing,parent_structure.facing)) == false:
+	if next == null or next.inventory == null or next.inventory.can_add_from_side(Globals.facing_difference(next.facing,parent_structure.facing)) == false:
 		return
 	var popped = inventory.pop()
 	if popped == null: