Facts and Features

The term zygosity is used to describe the degree of similarity of the genetic information in a pair of twins. There are monozygotic (identical) and dizygotic (fraternal) twins: The former are genetically identical because one fertilized egg divides in two. Dizygotic twins, however, are no more alike than siblings because two separate eggs are fertilized by two sperm. About a third of twins are monozygotic. Within these categories, there are subcategories of twin pregnancies based on whether the twins share a placenta or an amniotic sac.

The record for the time between twin births is 97 days. The likelihood of having twins increases if:

• the mother is a twin herself or has twins in the family
• IVF or assisted reproduction is carried out
• the mother is part of some ethnic groups that have a higher rate of twin births

"Das doppelte Lottchen" is a children's novel by Erich Kästner about a pair of twins, first published in 1949 and illustrated by Walter Trier.

According to historical accounts, King Gustav III of Sweden was convinced that drinking coffee was harmful to ones health. In the late 18th century, he sought out to prove its detrimental effects by offering a pair of twins, who had been sentenced to death, commutation of their sentence to life imprisonment on one condition: for the rest of their lives, one twin had to drink three pots of coffee each day, while the other consumed the same amount of tea.
The result was that the tea drinker died before his twin. Because both scholars who supervised the study died before the prisoners, the results remain inconclusive to this day. Nevertheless, this experiment is often regarded as the earliest long-term study in twin research.

Monozygotic (identical) twins develop when a single fertilized egg splits into two embryos within the first two weeks after conception. The embryos develop into two genetically identical babies who share nearly 100% of their genes and are almost always of the same sex. In some cases, however, the embryo splits later than usual, after the body's left-right axis has begun to develop. These twins are referred to as mirror-image twins because they may exhibit mirrored physical characteristics, such as opposite handedness or birthmarks on opposite sides of the body. Approximately 25% of identical twins are estimated to show mirror-image characteristics.

With a quick selfie, anyone can use Google Arts & Culture to find their art lookalike within thousands of years of art and cultural history. Check it out for yourself and find your twin!
https://artsandculture.google.com/camera/selfie

In botany, only one plant is known to exhibit twin-like characteristics: Linnaea borealis (in the honeysuckle family), commonly referred to as the "twin flower". Linnaea borealis is an evergreen, creeping subshrub featuring fragrant, bell-shaped flowers that grow in pairs on a slender stem. The twinflower plant is found in colder coniferous forests, for instance, in the northern regions and high mountain ranges of Eurasia and North America.

The frequency of twin births in Germany is around 1.2%, and globally, it is about 1.1%. Since the 1980s, the worldwide twin birth rate has risen by one-third, from 9.1 to 12.0 twin births per 1000 births, amounting to approximately 1.6 million pairs of twins per year.

A digital twin is a virtual model of a physical object or system that is updated in real time using computer-generated data. This precise reflection encompasses the object's entire lifecycle and can model anything from a single product to entire processes, services, or assets, such as factories and complete cities. This can be done regardless of whether the real-world object already exists or is still in the planning stages.
For instance, the EU initiative "Destination Earth" is currently developing a highly precise digital model of the Earth to find answers to the fundamental question of how climate change and extreme events impact our planet and how they will unfold in the future. The earth is essentially receiving a virtual replica of itself.

“Twins Days” is the largest twin festival in the world and takes place every year in Twinsburg, Ohio (USA).
https://twinsdays.org/ 

The people of the Yoruba, an ethnic group from West Africa, are convinced that their specific diet, which includes okra leaves, influences the rate of twin births.
Approximately 20% of births in this population are twin births.

In the early 20th century, the mirror-like technique of decalcomania became a defining element of the Surrealist artist Max Ernst's work. For this technique, a thin layer of oil paint is applied to a sheet of paper, which is then folded in half and pressed together. After subsequently unfolding the paper, a mirror-image pattern of random bubbles and branches are revealed. Max Ernst used these diverse surface structures as inspiration for creating landscapes, figures, and monstrous creatures, which are commonly referred to as his soul landscapes.