Investigators might analyze a wide range of specific features indicative of a person's handwriting, such as letter form and proportion, pen movement and position, writing speed, letter and word spacing, and the use of decorations, punctuation, spelling, and grammar. They may also consider broader characteristics such as school education, gender, age, cultural background, mental ability, and physical condition. Handwriting is a non-verbal means of communication that is unique to each individual human being. It is very flexible - characters can be written in any style or script, at any size, using ink on paper or on other materials such as glass, metal, wood, or even sand! The quality of handwriting varies over time due to aging processes or because of illness, injury, or drug abuse. But even if someone changes his or her handwriting because of learning or habituating to certain techniques, it is still identifiable. Our handwriting is influenced by many factors outside of our control. These include our genes, brain chemistry, and environment. Handwriting experts say that some people appear to be born with natural skills for drawing or writing letters correctly while others are not. Some researchers believe there are different types of handwriting patterns - some associated with specific traits or behaviors - that emerge in children during their first few years of learning to write.