diff --git a/projects/riverbankcomputing.com/sip/fib.sip b/projects/riverbankcomputing.com/sip/fib.sip
new file mode 100644
index 0000000000..5e494b607d
--- /dev/null
+++ b/projects/riverbankcomputing.com/sip/fib.sip
@@ -0,0 +1,24 @@
+// Define the SIP wrapper to the (theoretical) fib library.
+
+%Module(name=fib, language="C")
+
+int fib_n(int n);
+%MethodCode
+    if (a0 <= 0)
+    {
+        sipRes = 0;
+    }
+    else
+    {
+        int a = 0, b = 1, c, i;
+
+        for (i = 2; i <= a0; i++)
+        {
+            c = a + b;
+            a = b;
+            b = c;
+        }
+
+        sipRes = b;
+    }
+%End
\ No newline at end of file
diff --git a/projects/riverbankcomputing.com/sip/package.yml b/projects/riverbankcomputing.com/sip/package.yml
new file mode 100644
index 0000000000..78462d7d38
--- /dev/null
+++ b/projects/riverbankcomputing.com/sip/package.yml
@@ -0,0 +1,30 @@
+distributable:
+  url: https://www.riverbankcomputing.com/hg/sip/archive/{{version}}.tar.gz
+  strip-components: 1
+versions:
+  url: https://www.riverbankcomputing.com/hg/sip/tags
+  match: /rev\/\d+\.\d+\.\d+/
+  strip:
+    - /^rev\//
+dependencies:
+  python.org: ^3.11
+  linux:
+    tea.xyz/gx/cc: c99
+build:
+  script:
+    - python-venv.sh {{prefix}}/bin/sip-install
+    - python-venv.sh {{prefix}}/bin/sip-build
+    - python-venv.sh {{prefix}}/bin/sip-distinfo
+    - python-venv.sh {{prefix}}/bin/sip-module
+    - python-venv.sh {{prefix}}/bin/sip-sdist
+    - python-venv.sh {{prefix}}/bin/sip-wheel
+provides:
+  - bin/sip-install
+  - bin/sip-build
+  - bin/sip-distinfo
+  - bin/sip-module
+  - bin/sip-sdist
+  - bin/sip-wheel
+test:
+  script:
+    - sip-install --target-dir .
\ No newline at end of file
diff --git a/projects/riverbankcomputing.com/sip/pyproject.toml b/projects/riverbankcomputing.com/sip/pyproject.toml
new file mode 100644
index 0000000000..cb1019eddf
--- /dev/null
+++ b/projects/riverbankcomputing.com/sip/pyproject.toml
@@ -0,0 +1,8 @@
+# Specify sip v6 as the build system for the package.
+[build-system]
+requires = ["sip >=6, <7"]
+build-backend = "sipbuild.api"
+
+# Specify the PEP 566 metadata for the project.
+[tool.sip.metadata]
+name = "fib"
\ No newline at end of file