Electronic video images may show a varying degree of detail. That is evidenced by the contrast between standard television broadcasts and those called High Definition (HD). Television was originally displayed on a Cathode Ray Tube or CRT (also called the "picture tube"). The CRT reproduced the image on its screen by shooting an electron beam horizontally at the rate of about 60 times per second. To a large degree, the number of horizontal lines determined how detailed the video appeared. The more lines, the smaller the lines, the greater the detail of the picture.