By adopting a sedentary way of life, the Neolithic groups increased their awareness of territoriality. During the 9600-6900 BCE period in the Near East, there were also innovations in arrowheads, yet no important changes in the animals hunted was detected.
3. Poor screen preparation is a major cause of pinholes. Particles of dirt, wood frame chips, and dust remaining on the fabric during coating will be trapped in the emulsion. Opaque, they will block light from hardening the emulsion beneath them, so that the emulsion in these small areas will wash away after exposure.
The two pieces of plastic or aluminium are drilled to a size slightly larger than the rivet. The pop rivet is passed through both holes in the sheet plastic / aluminium. Rivet gun pushed over pin and handles squeezed together. The rivet pliers are pushed on to the pin of the rivet and the handles are pulled together. As this happens the pin head is pulled into the rivet and the end of the rivet is expanded.