consisted of a series of makeshifts and compromises introduced piecemeal when the shortcomings of the system being used became noticeable. Some signs acquired a variety of sound values. Some were used to clarify the sense of other groups, although they themselves were not pronounced at all. (These are called determinatives.) Thus “ti” when it meant “arrow” (and certain other implements) was accompanied by a sign which by itself read “gish” and meant “wood,” but which, used as a determinative, merely indicated that an implement of wood was referred to. Similarly, place-names were accompanied by the sign “ki,” meaning “earth,” divine names by the star sign, and so on. Nevertheless, the fact that phonetic values became attached to most of the signs made the rendering of grammatical endings, and, in short, of true speech, possible. [94]From Protoliterate times onwards, officials, and later also private persons, owned seals with which they could mark merchandise or documents. The shape of these seals was peculiar and remained characteristic for Mesopotamia until the end of its independent existence in Hellenistic times. They were small stone cylinders carrying on their circumference an engraved design which could be impressed on a tablet or on the clay sealing of a jar or bale of goods. Since the purpose of the seal design was the making of an individual and recognizable impression, its engraving at all times challenged the inventiveness of the Mesopotamian artists, who responded with outstanding success. (In our illustrations the rolled-out impressions, not the seals themselves, are shown. But see Figs. 35-9.) [95]The inlays consisted of terra cotta plaques set in among the clay cones which covered the walls. The carved figures were executed in stone and fixed to the wall with copper wire through loops drilled in their backs (Fig. 18).