As promised, here is another idea for using a cake stencil (method explained here). This look is quite graphic and bold. It is a lemon cake filled with lemon curd that I made a while back. I'd have to say this cake is a contender as one of my favourite cakes I've ever made. Sadly I no longer have the recipe because my leaky kitchen ceiling flooded my only copy and it was destroyed.
R.I.P. lemon curd cake recipe - you are sadly missed.