Welcome Industries’ Visual Measuring Cups
Right at the center of the Venn diagram between “Loves Cooking” and “Loves Pie Charts” comes this set of four measuring cups, the shapes of which represent whatever fraction they are — e.g. 1 cup is a full circle, ½ cup is a semicircle, etc.
They’re 1) made from BPA-free plastic and are dishwasher safe, 2) can work well for legally blind people, 3) could probably be used to teach kids basic fractions, 4) make a great novelty gift besides, and 5) yes, they do stack together.
The set is $24 on Amazon.