If you have an itchy arm, looking in the mirror and scratching the mirror image of that arm (the one that isn't bothering you) will help, although it only provides a quarter of the relief of scratching the itchy arm.

See the source article by following the link below:
If you have an itchy arm, looking in the mirror and scratching the mirror image of that arm (the one that isn't bothering you) will help, although it only provides a quarter of the relief of scratching the itchy arm.