Mirror image twins. Reversed asymmetry they called it. One had a mole on the left cheek the other on the right. One right handed, the other favouring the left. To an onlooker, the differences are apparent but the twin needs no mirror to see herself.
It was easy to replace the wardrobe mirror with plain glass and as she stood there in the cupboard with the appearance of blood coming from her eye, for an instant, her twin was fooled, and fainted, catching her eye on a chair as she fell.
“Only a joke!”
Blood streamed from her sister’s eye.
D.M. almost 5 years ago
Hence the term "evil twin"?