In Dialogue Concerning the Two Chief World Systems (1632), Galileo Galilei observed:

"As I was scraping a brass plate with a sharp iron chisel... [I] heard the plate emit a rather strong and clear whistling sound: on looking at the plate more carefully, I noticed a long row of fine streaks [in the brass filings] parallel and equidistant from one another."

With a few lifetimes' worth of notable observations, it's understandable that this gem of Galileo's brilliance is mostly overlooked. But this observation is one of the first recorded studies of a little-known field now called Cymatics.

Cymatics is the study of the visible patterns produced by sounds and vibrations. The sound is often thought of as being invisible, but every sound has a shape and it is relatively easy to set up an experiment where you can see this in action. When sand is poured on a large metal plate and various tones are produced near the plate, the sand gathers into geometric patterns that reorganize themselves at various pitches, producing sometimes dazzling Mandalas in seconds.

Why ordered patterns instead of arbitrary shapes? The answer to this may shed light on the big graphic design question: what makes good design? It may also explain why the same four chords have dominated the popular music scene for generations. Seriously.

Ernst Chladni – known as the "Father of Acoustics" – was the first to actively study Cymatics (before the name was coined by Hans Jenny some fifty years ago). He would draw a violin bow across a large plate, wowing his 18th-century parlor guests as sand danced into precise shapes. Today people are still awed by artist and Cymatics researcher Alexander Lauterwasser who is carrying on Chladni's pioneering work by creating beautiful aural and visual experiences across the world.

What they and others have learned is that patterns of sound follow mathematical scales the same way frequencies appealing to the human ear do. People of varying cultures tend to come to a consensus that certain frequencies sound good together and others do not. For example, in our culture, essentially every popular song has used one of 13 scales. No matter what the genre is, the patterns produced by these scales just seem to work.

This helps to explain why there are rules to graphic design. There is a framework of visual order that is appealing to people just like the framework of musical scales is appealing to people. Certain proportions, harmonies and rhythms work together in design better than others, time and again, just like in the best music.

It would appear that there exists a pattern of graphic design we cannot see wrapped in the sounds we hear every day. Cymatics implies a geometric unity between shape and sound, reminding designers and clients alike that there indeed exists a fundamental framework of rules that the best design (and music) adheres to. This is not to say you cannot push the boundaries and bend the rules, just be careful not to play a sour note.