Believe it or not, there is a word for the shape that is universally recognized as the symbol of love. I first encountered the word in high school trigonometry, and it was plotted as a result of a polar function. That shape is called cardioid, which literally means heart-shaped, and it’s produced by plotting the function r(θ) = 1 – sin(θ). Technically, it follows the shape of an apple, with its rounded base, rather than the pointed tip with which we usually draw the shape.
The heart symbol can also be typed by pressing Alt+5 [on the numpad, on the right-side of the keyboard], just like this: ♥
As it turns out, there are other ways of plotting the curve, and MathWorld provided several other functions to plot the curve and achieve the perfect shape, using either rectangular, polar or parametric functions. (Source)
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