I have been meaning to make a π plate for years, and this spring I finally did. The plate includes about 800 digits--my favorite run of which is
999999--before spiraling off to infinity underneath the rim.
I'm generally wary of using pottery in the oven. S and I once had a beautiful hand-painted baking dish from Poland, and we followed all of the instructions for its use until it cracked in the oven. Typically, pottery should go into a cold oven and warm up as the oven does. That doesn't seem conducive to pie plates, since pie crusts usually go from the refrigerator or freezer straight into a hot oven, so the π plate remained unrealized. Then a student at Claymakers requested a class on pots for cooking, and the studio manager gave me a bag of thermal-shock resistant clay to test out in preparation for that.
I made two test plates, and glazed them with the two glazes I have that usually show texture the best. One showed the digits well, and the other did not. This made it easy to decide which plate to sacrifice to thermal shock testing.
After the empty plate survived going straight into a hot oven, I made
the best pie crust I've ever made, tucked it into the pie plate, stuck it in the fridge overnight, filled it with the best spinach, onion, and Gruyère quiche filling I've ever made (fresh whole spinach is key) and put it into a hot oven. It performed extremely well.
We ran the plate through the dishwasher, and learned it clearly hadn't vitrified at the temperature I had fired it to (^6). Given that earthenware is likewise porous and often used for bakeware, I'm not particularly worried about that.
The next test will be to make a pie in the other π plate, to make sure the success of the first one wasn't a fluke. Then we'll have to eat the pie, to make sure it's OK--all in the name of research, of course.