Have they changed over the years?
Heraldic design has evolved over the centuries to quite a considerable extent. In the earliest years of heraldry the designs were very simple, geometrical arrangements with very few objects placed on the shield. By the time we get to the early Tudor period, coats of arms were becoming much more complicated and thousands and thousands of people were getting coats of arms, so in order to make them all different to each other they seem to get much more complicated. There have been trends and fashions in heraldic design over the years. The late 18th century saw the introduction of what's known as landscape heraldry, where people would depict landscapes on the shield, perhaps a great military victory or some other kind of incident in their lives. Today we're returning to what we think of as being the medieval inspiration of heraldry, so we keep our designs as simple and geometrical as possible, include as few different colours and as few different objects as possible, to make the design as simple, clear, and identifiable as we can.