 This pattern has to be applied at a particular stock consistency; otherwise the pattern will be lost as the fiber flows back while the stock moves past the dandy (too wet), or fiber will pick out of the stock (too dry), causing surface disruption.As the fiber is displaced, localized areas of higher and lower density are produced in a laid pattern, and the pattern is also created on the paper's surface.The pattern is therefore apparent both as one looks through the sheet and as one views its surface.