The beam skipped blank areas of the screen. Things could be drawn in arbitrary order.

Vector displays are a now-obsolete alternative to raster scan displays. In vector displays, the CRT electron beam 'draws' only the lines and curves displayed. In raster scan displays, the image is a grid of pixel spots (a 'bitmapped' image), and the CRT beam repeatedly sweeps the entire screen in a fixed horizontal pattern (like in TV sets), regardless of which dots are turned on. Bitmap raster graphics require