Dance is a performing art form consisting of purposefully selected sequences of human movement. This movement has aesthetic and symbolic value, and is acknowledged as dance by performers and observers within a particular culture. Dance can be categorized and described by its choreography, by its repertoire of movements, or by its historical period or place of origin.[from wikipedia]

The practice of using colors to determine the temperature of a piece of (usually) ferrous metal comes from blacksmithing. Long before thermometers were widely available it was necessary to know what state the metal was in for heat treating it and the only way to do this was to heat it up to a color which was known to be best for the work.[from wikipedia]

A smiley (sometimes called a happy face or smiley face) is a stylized representation of a smiling humanoid face that is a part of popular culture worldwide. The classic form designed by Harvey Ball in 1963 comprises a yellow circle with two black dots representing eyes and a black arc representing the mouth.[from wikipedia]