Interest heightens visual acuity while fear and pain can temporarily blind one—just as rage can. The human eye takes several years to mature: to co-ordinate with its fellow; to recognise colour and texture, to define movement, to judge distance and size, to select and disregard, to change focus from near to mid and far distance, to interpret: in fact, to discriminate. As interest heightens visual acuity we need to provide a visually stimulating environment in schools. The teacher must, therefore, aim for a tension-free classroom, where each child feels he is valued and is making progress, and where the visual stimuli result in meaning. A good start is by classifying things—according to colour, shape, size, texture, use. 'Out of sight—out of mind' does not always mean a cupboard door or a curtain—it can be equally above or below eye level—or entangled with other competing visual stimuli.