Energy Conservation Tutor is an ambient display device that aims to encourage the residents to be conscious of the amount of electricity consumed at home. ECT generates large, brilliant, and endless unique kaleidoscope-type light patterns on the neighboring walls and ceiling. The less energy consumed in the house the brighter and the more stimulating the patterns of ECT; conversely, the more energy consumed the dimmer and the more diffused the patterns generated. ECT is an expressive ambient display designed to promote awareness of energy consumption levels, and aims to expand the idea of “interface display.”