As work progressed on the early medals, certain ideas began to form requiring a larger size. Modelled in clay as distinct from wax, a different technique was used but it was the plasticity of the material that encouraged me to use the gestural squeezing and probing of the fingers in evolving the ideas. Thus the simple composition of several of the reliefs illustrated is, to some extent, due to the nature of the clay. Another factor was the experience I had gained through understanding more of the techniques of the struck medal. The process used in both medal and coin production can be a combination of working in the positive and negative. Early Greek coinage stands out through its bold relief, due partly, to the fact that the original design would have been carved in intaglio in a hard metal, used as the die, from which the coins would be struck. This is a skilled and exacting process demanding a broad treatment of form resulting in coins of great beauty. In later years, generally accepted as in the fifteenth century, modelling, as distinct from intaglio engraving, became the preferred form for the development of the medals, exampled by the masterpieces of Pisanello. As engraving techniques developed and finer detail achieved, the combining of modelling and engraving, along with working in both the negative and the positive came into use.Certain of my own relief sculptures have been conceived and worked on in this way. A start has been made by squashing and pressing fingers, thumbs and fragments of material as negative forms into a bed of soft clay, using the plasticity of the material to express the broad sweep of clouds and the silhouette of wheeling birds as they move across the sky. As the clay hardens, more detailed work can be added by engraving in the negative before a plaster cast is made on which more detail can be added on the positive.