Please help me find this short story that I read about 20 years ago:
The story is set in the late 1800 / early 1900 in an American / English city, where a young man rents an apartment whose former tenant has committed suicide.
From one of the windows he can look into another apartment, and he starts a strange game with the young girl who lives there: he makes a gesture, and she imitates it with uncanny speed and precision, as if the she were his mirror image.
Night after night, the game becomes ever more complex and the girl mimics even the most elaborate gestures; the main character starts to get suspicious when he writes down beforehand the gestures he intends to make, and discovers afterwards that he has completely ignored the list: it transpires that it was the girl who picked the moves, and in all these nights she was hypnotizing / training the main character to bend his will to hers.
The story ends with the girl mimicking the act of making a noose and hanging herself, thus explaining the suicide of the previous tenant.
I cannot remember whether the main character survives; I also have a dim memory of a spider theme - either the girl was compared to a Black Widow, or there was a spider web covering one of the windows, or the girl was actually an illusion cast by a spider.
Thanks for any hint!
