Is there a set of equations out there that gives a heart without any other marks? It needs to be in the form of $y = f(x), r = f(\theta)$ or $X_T ,Y_T$ (parametric equations) There needs to be a variable '$a$', which gives a different shape for a different value of $a$.
Edit 1:Also, could you state the best value for $a$? This is opinion based, but it takes me ages to draw one using trial and error
Edit 2: Sorry guys, I am being a bit of a pain aren't I?! This has turned into a challenge now, but could you specify rad/deg, Parameters for $\theta, x/y, and T$? As I have said, I am going to draw this by hand, and I might even LEGO it, so can you give me something suitable for LEGOing?