These layout trays allow you to make up your own paper-faced mixed glass sheets in 1cm x 1cm tiles. There are 841 spaces (the grid is 29 x 29).  Simply lay the tiles face-up into the individual tile recesses in the tray to make the pattern of your choice and then apply your brown paper to create the mosaic sheet. The tray holds the tiles in position so need to worry about wonky lines or tile movement when you adhere the paper to the tiles. The jigs make full sheet sizes of 325mm x 325mm but you can adjust the numbers of tiles, and therefore the dimensions, to suit your needs.