Those who look so much alike are often very different people. It can be seen even on photos.
Since childhood parents who can't see any evident difference between twins start "endow" them with different temperaments: one smiles more often, another one is often angry; one eats much, another one easily falls asleep. Parents do not often apprehend that this starts to influence further maturing of their children.
Rustam and Nadir, 11 years old
The boys study at school and have not exploited their resemblece yet. Nadir is naughtier, Rustam is assiduous and calm, he often has to help his brother out of troubles.
However twins almost never have similar characters.
Adilya and Anelya, 17 years old
Adilya is hot-tempered, likes to party and plans to become a fashion designer. Anelya prefers to stay at home and keep a house. She's responsible and resolute, plans to be a doctor.
Getting older twins start exploiting their resemblence and like to mislead others by pretending to be his/her twin. Their first victims are usually teachers.