  The purpose of this work is to present the concept of an autonomous
Stirling-like engine powered by anisotropy of thermodynamic fluctuations.
Specifically, simultaneous contact of a thermodynamic system with two heat
baths along coupled degrees of freedom generates torque and circulatory
currents -- an arrangement referred to as a Brownian gyrator. The embodiment
that constitutes the engine includes an inertial wheel to sustain rotary motion
and average out the generated fluctuating torque, ultimately delivering power
to an external load. We detail an electrical model for such an engine that
consists of two resistors in different temperatures and three reactive elements
in the form of variable capacitors. The resistors generate Johnson-Nyquist
current fluctuations that power the engine, while the capacitors generate
driving forces via a coupling of their dielectric material with the inertial
wheel. A proof-of-concept is established via stability analysis to ensure the
existence of a stable periodic orbit generating sustained power output. We
conclude by drawing a connection to the dynamics of a damped pendulum with
constant torque and to those of a macroscopic Stirling engine. The sought
insights aim at nano-engines and biological processes that are similarly
powered by anisotropy in temperature and chemical potentials.
