The moulds used in these machines are made out of metal and cost roughly V$50,000 toproduce. The moulds have finite lives, eventually losing their precise shape. The bricks haveto be manufactured to a very precise tolerance, otherwise they will not fit together properly.Prybloxx minimises the numbers of moulds required by aiming for long production runs of eachgiven part.The colour of the brick is determined by the colour of the plastic pellets being fed into themachine. The cheapest and easiest way to change colours is simply to start feeding a newcolour of pellets into the machine, discarding the initial outflow while the remainder of theprevious colour of plastic is forced through the machine.