Halloween - Nice Fan You Got There.
Laurie has ran back to the Doyle House, sent Tommy upstairs, and ran around to the front of the sofa where she arms herself with a sewing needle. There is a window in the back corner that is open with the curtains blowing. Look outside the window and behind the blowing curtains you can plainly a see a huge studio fan simulating wind outside.
The movie, better seen in the widescreen version