The ancient Mayans were known for their advanced culinary techniques, and they had a unique way of tempering chocolate. In their kitchens, they used a built-in chocolate tempering machine made of stone. This machine consisted of a large stone bowl with a smaller stone cylinder inside. The Mayans would heat the chocolate in the bowl and then use the cylinder to stir and cool the chocolate, ensuring that it reached the perfect temperature for tempering. This ancient kitchen innovation allowed the Mayans to create delicious and perfectly tempered chocolate for their various culinary creations.