layers of nets for example mesh and or sheets with holes to even out the steam concentration close to the powder layer fig2 a and 2 b shows how an uneven distribution of moisture 21 obtained by applying steam 3 through e g a nozzle 25 can be used for design effect purpose different amount of moisture 21 in different parts of a single colour powder but not yet pressed surface gives a visual colour difference of the different parts by controlling where on the surface the moisture content is higher a wanted design effect 22 can be generated see fig2 b in the pressed surface 24 of the panel even if only one unicolored powder layer is applied on the core 1 by controlling the relative movement between a core 1 with the powder mix layer 2 and one or several steam outlets a controlled variation of the content of moisture 21 in the powder can be achieved this variation of moisture content will after pressing be visible as color differences 22 on the ready surface 24 one or several of the steam outlets could be fixed on a robot arm and their position in relation to the scattered board could then be controlled in all directions the steam outlets.