Appreciation of sculpture depends upon the abi8lity to respond to form in three dimensions. That is perhaps why sculpture has been described as the most difficult of all arts; (1)_______________________. Many more people are 'form-blind' than colour-blind. The child learning to see, first distinguishes only two-dimensional shape; it cannot judge distances,depths. Later, for its personal safety and practical needs, it has to develop(partly by means of touch) the ability to judge roughly three-dimensional distances. (2)_______________________. Though they may attain considerable accuracy in the perception of flat form, they do not make the further intellectual and emotional effort needed to comprehend form in its full spatial existence.