In this talk, we present a simple explicit formula for the curvature of planar Bezier curves generated by Farin's method. This formula is easily obtained by the invariance under subdivision property and from it there can be derived conditions on the eigenvalues of a general matrix and the initial edge of the control polygon that give rise to aesthetic Bézier curves. This approach gives a common framework to the previous works and recovers the results as particular cases. For more details we refer to A. Canton, L. Fernandez-Jambrina, M.J. Vazquez-Gallo. Curvature of planar aesthetic curves. Journal of Computational and Applied Mathematics, 381:113042, 2021.