  Chaotic dynamics are ubiquitous in nature and useful in engineering, but
their geometric design can be challenging. Here, we propose a method using
reservoir computing to generate chaos with a desired shape by providing a
periodic orbit as a template, called a skeleton. We exploit a bifurcation of
the reservoir to intentionally induce unsuccessful training of the skeleton,
revealing inherent chaos. The emergence of this untrained attractor, resulting
from the interaction between the skeleton and the reservoir's intrinsic
dynamics, offers a novel semi-supervised framework for designing chaos.
