Customized Parametric Curves

Examples of parametric curves, created by single pairs of non-piecewise parametric equations. I developed this process for creating such curves (or at least if someone else beat me to it, I'm unaware). My process utilizes and reinforces high school level Math skills (domain/range, function transformations, function addition, function composition, writing sinusoid equations, parametric equations). Inspired by the "Batman Equation" of 2011 and Wolfram Alpha's "person curves." How-to article coming up in NCTM's Mathematics Teacher: Learning and Teaching magazine, June 2020.