For example, six to eight moving heads can create a textured blue “night” effect on the stage floor while applying amber light to the actors during one scene - this can create a sensation of dusk or night. At the flick of a switch, the fixture can change to an animated red “fire” effect for the next scene. Attempting this transition with traditional lighting fixtures could require as many as thirty instruments. In this circumstance, the automated fixtures are not doing anything that could not be achieved using conventional fixtures, but they dramatically reduce the number of lights needed in a rig. Other features of automated fixtures, such as rotating gobos, are also possible with conventional fixtures, but are much easier to produce with intelligent fixtures. Active use of automated lights suggests that the luminaire is used to perform tasks which would otherwise require human involvement, or be simply impossible with conventional fixtures. For instance, a number of moving heads producing tightly focused, pure white beams straight down onto the stage will produce a fantastic effect reminiscent of searchlights from a helicopter (especially if a smoke machine or hazer is used to make the beams visible). To recreate such an effect without intelligent lights would require at least one human operator seated directly above the stage with a followspot, which would generally be considered to be too expensive for such a small effect. Moving head fixtures are often divided into spot, wash lights and beam lights. They vary in use and functions, but many companies offer profile and wash versions of the same model of light. Profile lights generally contain features like gobos and prisms, whereas wash lights have simpler optics and a wider beam aperture resulting in wider beam angle, which may be altered by internal lenses or “frost effects”. Wash lights are more likely to have CMY colour mixing although it is common for high-end spot lights to have such features too. Spot units are generally used for their beam effect (usually through smoke or haze) and the ability to project texture, whereas wash lights tend to be used for providing a stage wash. Beam lights are often built much like the spot in terms of functionality aside from one key difference: beam lights use a wide lens to make an even more extreme beam. A typical spot has a beam angle from 15 to 35 degrees, whereas