diff --git a/doc/internals/pattern.dia b/doc/internals/pattern.dia
new file mode 100644
index 000000000..3d1321581
Binary files /dev/null and b/doc/internals/pattern.dia differ
diff --git a/doc/internals/pattern.pdf b/doc/internals/pattern.pdf
new file mode 100644
index 000000000..a8d8bc933
Binary files /dev/null and b/doc/internals/pattern.pdf differ