Question Title

* A "cardioid" is a geometric curve that's kinda romantic. It looks like the "heart" shapes we use on Valentine's Day cards and decorations. A cardioid can be made by taking a circle and then rolling another circle of the same radius around its circumference. If you track a point on the circumference of the outer circle it will trace out the shape of a cardioid.
a moving graphic of two circles making a cardioid

"Pi" is really important to circles. (And it's delicious! 😉)
Which jokey math expression uses the letter pi?

Question Title

* APH is happy to provide Braille Refresher questions.
APH logo

T