The present invention provides a method of coating a surface with a slip resistant coating. For example, a user-entered authentication code can be compared to an authentication code, and a user-selected element of the structure can be compared to a destination element resulting from following an authentication path through the structure beginning at a starting element. A screen is disposed at the bottom of the trough such that whole berries are conveyed over the screen while the undesirable components pass through the screen The preferred embodiment of the screen has a non-uniform cross-section to improve the efficiency of removal the undesirable components without clogging or requiring constant maintenance. The second masks intersect with the first masks to form a plurality of overlapping regions. 5P, and a second upper cladding layer of 0.