The earliest example of equine footwear we have is made of animal hide and dates from about 600 B.C. This primitive hoof protector looks more like a horse bootie than what we think of today as a horseshoe. It was probably stuffed with dried grass or other available natural material and tied on with hide thongs.
The spiral model is a software development process combining elements of both design and prototyping-in-stages, in an effort to combine advantages of top-down and bottom-up concepts. The spiral model was defined by Barry Boehm in his article A Spiral Model of Software Development and Enhancement from 1985. This model was not the first model to discuss iterative development, but it was the first model to explain why the iteration matters.
ents lived). Between 1963 and 1964, however, Bearden took an artistic step that would alter the direction of his work and bring him international attention. The Dovecollage was among twenty-one works Bearden made during his involvement with Spiral, an organization of fifteen African American artists formed in July 1963, one month