A primary school class use black and white squares to represent the pixels that make up images as bitmaps. In an exercise to show how computer graphics are made, two teams are given pictures to make out of just black and white squares. The instructions are in binary code; a 0 means a white square and a 1 a black square. Their images lack detail when made up out of big squares, so science presenter Minna Kane gives them smaller squares to use. These mimic using more pixels, or a higher resolution. On a computer they could use up to 16 million colours to make up their images, not just black and white. A practical demonstration of pixels, bitmaps, binary and resolution in computer graphics. Teacher notes: Pupils could create their own bitmap designs using either small pieces of black and white paper or on the computer using art software. Once the basic design is finished, they could create the same image but use smaller squares to demonstrate how more pixels make a clearer image.