Figure 1:

Shapes of the set $\{b:{\lambda }_Q{b}^{\mathsf{T}}Qb+{\lambda }_R\Vert b{\Vert }_2^2=1\}$ (level curve) for various pairs of regularization parameters: (a) assumed strong connections between variables is neglected, (b) moderate tendency for coefficients of the solution to be similar to each other and (c) strong tendency for coefficients of the solution to be similar to each other.