Why & How do I see this heart-shaped cardioid formed in my cup

Ok, first of all if you don’t know what I’m talking about, I’m talking about this shape in a cup of tea/coffee (or even water). I first got curious about this weird shape appearing in my cup a few…

Cardioids in coffee cups - Chalkdust

calculus - Cardioid in coffee mug? - Mathematics Stack Exchange

Originals Original Content

I Heart Cardioids – David Richeson: Division by Zero

Cardioid

Microphone Pickup Patterns - What does that shape mean? - JustAskJimVO

The Equation of the Heart – The Academies Online

Why do we see the heart shape in a coffee cup?

calculus - Cardioid in coffee mug? - Mathematics Stack Exchange

cardioid – Bean Thinking

Cardioid Equation and Shape - Rectification - Engineering