Nice job Bruce. I’ve messed with doing this a little and I find it to be very tedious for me. I’ve lost some sensation in my fingers due to spinal stenosis, so I have a hard time picking up tiny things with my meat hooks. I have to use tweezers, so it is a little bit of a pain in the butt.
As you say, the know the real trick to making these things look realistic is the hot sand. It’s the final detail and without it I’m not sure it will ever reach your standards. As you continue your experimentation with parquetry I know you will be warming up sand in your future. 

.................. John D....................