Cubic 2D

f(x,y)= A10 x + A01 y + A20 x^2 + A11 xy + A02 y^2 + A30 x^3 + A21 x^2 y + A12 xy^2 + A03 y^3

Each parameter sets the value of the coefficient of a different term. In the Pisces user interface, A[i,j] is called coef_x^{i}y^{j}.