Stencil is a very accessible technique used for decoration which renders beautiful results. It delivers your message in walls, t-shirts, and even cakes.
Basically, we cut out a surface, and the parts taken out of the paper form the drawing that will be printed. I think the picture below will help.

I really enjoy playing around with stencil, so I experiment with detailed images, such as the Nacho Libre below. Anyway, I have also made cakes embellished with only a couple of hearts and find it beautiful. Since Rebeca asked me, I have prepared this post to explain how to make stencils.