Answer:
Synaesthesia
Step-by-step explanation:
Is a medical condition in which the brain do different connections among the senses. In this way when a person is writing can smell the letters, or when a person is writing his or her name, is a must to be written with different colors.
Scientist do not know exactly how this condition appear and they are trying to understand how it works. This condition seems to be inheritance and is more common in people with autism or some condition of the autism spectrum.
Hope this info is useful.