1. Donut hole
While bakers today can make delicious pastries of any shape and size, in the past it used to be difficult to get the edges and the middle of a pie equally baked. So, bakers came up with this particular shape which didn't cause any problems.
2. Sunglasses
While its name suggests that this object only has one purpose, it is not that simple. Dark glasses were invented by Arctic people as a means of protecting their eyes from the dazzling snow. They then became widespread among the judges in 12-century China - they wore glasses to hide their real emotions from witnesses.
3. Notebook margins
Originally, margins weren't made to provide space for teachers' remarks. The margin was initially intended for books that fell victim to mice and rats who liked to gnaw on paper. So, to prevent parts of information along with the paper from being eaten, people started to leave empty spaces at the edges, where most of the damage was likely.
4. Dimples on golf balls
At first, golf balls were absolutely smooth. But with time, golf players realized that the balls with the best properties were old, scuffed and cracked. As a result they kept using the same old balls for years. When manufacturers became aware of this tendency, they started to produce artificially aged dimpled balls.
5. Half belts
Many coats and jackets have a small piece of cloth or leather. This is known as a half belt. They first appeared on military greatcoats centuries ago. As the greatcoats were immensely wide, they had to be tailored with pieces of cloth, whereas during the night, the half belts could be unstrapped and the greatcoat could be used as a blanket. Though times have changed, half belts still remain.
6. Holes in padlocks
As padlocks are generally used to lock doors and gates outside, they quickly get out of order because of the rain. Usually, when this happens, most people tend to buy a new one, but the small holes at the bottom are made for pouring engine oil inside. After which, the key will turn in the lock without any difficulty.
7. Stripes on headphone jacks
Have you noticed that all headphone jacks have 2 or 3 stripes on them. But, these stripes are not made for decoration. There are wires going to both headphones from every stripe and if they weren't there, you would only hear sound coming from one of the headphones.
8. Ridged edges of coins
In the early 16th century, grooves were engraved into the edges of coins. At the time, people would cut off small amounts of precious metal from coins to sell, and would pass on the damaged coins at full value. To stop this from happening, a special process known as reeding was introduced. It consisted of carving a series of grooves on the edges of the coins so that it would be easy to see if a coin had been tampered with. While hardly anyone clips coins nowadays, reeding has remained a long-standing tradition.
