the idea that the various colours used in tartan have a specific meaning is purely a modern one. one such myth is that red tartans were "battle tartans", designed so they would not show blood. it is only recently created tartans, such as canadian provincial and territorial tartans (beginning 1950s) and u.s. state tartans (beginning 1980s), that are designed with certain symbolic meaning for the colours used. for example, the colour "green" sometimes represents prairies or forests, "blue" can represent lakes and rivers, and the colour "yellow" is sometimes used to represent various crops.