I have been trying to do different designs with the least amount of work in laying out a pattern to work by.
I started by scanning a plastic structural piece made of plastic. Saving it as an image. Using my photo editor program "Photo Studio" to size the image back to the original size of the scanned piece.
Printing it with my Inkjet printer on the best setting, this put down the most ink on the paper.Running the paper through the printer twice to get more ink on it.
I haven't tried photo paper, I think it might let the ink transfer best.
I prepared the surface by sanding it with a block and medium grade sand paper to get a flat surface.
Next I wet the surface making sure that it was to the point that I could scrap off the material with my fingernail.
Wet the printed picture and place it where you want the pattern on the work surface and press it down, making sure it doesn't move or it will blur the design.
Lifting the edge of the paper and checking to see how the printing is transferring the pattern. When the transfer to the surface can be seen, remove the paper carefully. Colored ink seems to transfer best.

Cut the design in the material the same as for the bricks.