Neon is very impressive as a sign and is used widely by companies who want to make a visual impact upon the passersby. Different gases pumped into the glass tubing creates a variety of colours when it is charged with electricity. The glass tubing is heated and bent to the shape of the layout. Neon works very well when external temperature is controlled, allowing internal installation to be the ideal situation. Of all the signs, neon can be the most complicated and most expensive based on the price per square foot, yet it is also the most beautiful. Neon signs may require permits by the city and Hydro, as well as electrical work.