decor...I am familiar with the technique. It is familiar to the one done to put patterns in concrete. In that method they use a flexible sheet, sort of a rubber material, that has the pattern cast into it in reverse. That sheet is positioned on the fresh trowelled concrete and then backed with plywood or such and then enough weight is added to press the pattern into the concrete. Then the sheet is moved to the next clean position and repeated. Those patterened sheets are available pre-made. However, if you want to do your own custom patern, you could lay the objects you want in your pattern into a small frame and then pour a flexible material (RTV?) over it to create your pattern sheet, then use as described above.