From a blog post:
Solve the parametric equation for y (does SO allow math formatting?)
x^2 + (5y/4-sqrt(abs(x)))^2 = 1
sqrt(1-x^2) = 5y/4 - sqrt(abs(x))
y = 4/5*(sqrt(1-x^2)+sqrt(abs(x)))
MASS::eqscplot(0:1,0:1,type="n",xlim=c(-1,1),ylim=c(-0.8,1.5))
curve(4/5*sqrt(1-x^2)+sqrt(abs(x)),from=-1,to=1,add=TRUE,col=2)
curve(4/5*-sqrt(1-x^2)+sqrt(abs(x)),from=-1,to=1,add=TRUE,col=2)
