How was the bicycle invented?
Same way most inventions are done.
A man with an idea got together with someone who could build
what he described. Later someone else thought of an improvement and
found someone to build a slightly different version, which has kept
happening ever since.
The earliest bicycle was a wooden scooter-like contraption
called a celerifere; it was invented about 1790 by Comte Mede de
Sivrac of France. In 1816, Baron Karl von Drais de Sauerbrun, of
Germany, invented a model with a steering bar attached to the front
wheel, which he called a Draisienne. It has two wheels (of the same
size), and the rider sat between the two wheels, but there were no
pedals; to move, you had to propel the bicycle forward using your
feet (a bit like a scooter). He exhibited his bicycle in Paris on
April 6, 1818.