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+Async "Eratosthenes" Example
+============================
+
+The Python language provides keywords for asynchronous operations, i.e.,
+"async" to define coroutines or "await" to schedule asynchronous calls in the
+event loop (see `PEP 492 <https://peps.python.org/pep-0492/>`_). It is up to
+packages to implement an event loop, support for these keywords, and more.
+
+The best-known package for this is `asyncio`. asyncio offers an API that allows
+for the asyncio event loop to be replaced by a custom implementation. Such an
+implementation is available with the `QtAsyncio` module. It is based on Qt and
+uses Qt's event loop in the backend.
+
+`trio` is another popular package that offers a dedicated `low-level API
+<https://trio.readthedocs.io/en/stable/reference-lowlevel.html>`_ for more
+complex use cases. Specifically, there exists a function `start_guest_run` that
+enables running the Trio event loop as a "guest" inside another event loop -
+Qt's in our case, standing in contrast to asyncio's approach.
+
+Based on this functionality, two examples for async usage with Qt have been
+implemented: `eratosthenes` and `minimal`:
+
+.. image:: eratosthenes.svg
+   :alt: Async example: Eratosthenes
+   :width: 400
+
+* `eratosthenes` is a more extensive example that visualizes the Sieve of
+  Eratosthenes algorithm. This algorithm per se is not one that is particularly
+  suitable for asynchronous operations as it's not I/O-heavy, but synchronizing
+  coroutines to a configurable tick allows for a good visualization.
+* `minimal` is a minimal example featuring a button that triggers an
+  asynchronous coroutine with a sleep. It is designed to highlight which
+  boilerplate code is essential for an async program with Qt and offers a
+  starting point for more complex programs.
+
+While `eratosthenes` offloads the asynchronous logic that will run in
+trio's/asyncio's event loop into a separate class, `minimal` demonstrates that
+async functions can be integrated into any class, including subclasses of Qt
+classes.