Haha, I'm not sure I'm going to get a job as a tiler any day soon, but I enjoyed playing with this technique to create my grouted dish.
 
15cm x 15cm with transparent triangles of clear, yellow and red glass.  Fired once to tack the triangles to a clear layer of glass.  Fired long enough to seal the glass together but not to soften the edges.  Then mixing green glass powder into a paste and 'grouting' the piece to ensure the depth of the piece is 6mm everywhere.