README: Describe "Pycopy Zen".
@@ -37,6 +37,42 @@ and a number of bare-metal microcontroller systems (see below). Ports to
other systems can be implemented easily. POSIX port (nicknamed "Unix port")
is the reference port of Pycopy.
+The Pycopy Zen
+--------------
+
+[Just as "big Python"](https://www.python.org/dev/peps/pep-0020/), Pycopy has
+its "Zen". The main principles of Pycopy are **simplicity**, **minimalism**,
+and **light-weightedness**.
+
+At the same time, Pycopy strives to be a full-stack language and
+be compatible with wider Python ecosystem. The Pycopy project resolves
+these seemingly conflicting goals in a well-known and elegant way: by
+being a multi-level project, and by providing flexible configuration options.
+Specifically, there's a well-defined lightweight core written in C,
+defining the "native Pycopy language". Above it, a number of options are
+provided, implementing additional functionality (oftentimes offering more
+CPython compatibility). For example, on top of the core, "native Pycopy
+builtin modules" are provided, defining the native Pycopy API, which
+provides a subset of CPython's modules functionality, and at the same time,
+some extensions to it (driven by Pycopy's goal to be efficient). These native
+Pycopy modules are clearly namespaced, to allow to implement modules fully
+compatible with CPython API without any changes to the main project.
+
+On top of this primary project, there are separate projects to further extend
+Pycopy functionality and achieve full-stack ecosystem. For example, there's
+a [pycopy-lib](https://github.com/pfalcon/pycopy-lib) project (see below) to
+implement a fully compatible CPython standard library for Pycopy.
+
+Finally, on top of that infrastructure, there is an ecosystem of third-party
+packages, which are managed by the Pycopy users themselves.
+
+The art of working with Pycopy is to understand where a particular feature
+belongs. Just as with CPython, it's almost never the core project, and almost
+always users' third party packages.
+
+[Contributors' Guidelines](https://github.com/pfalcon/pycopy/wiki/ContributorGuidelines)
+further elaborate on some points touched above.
+
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