diff --git a/.gitignore b/.gitignore
index b6e4761..487b123 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,129 +1,10 @@
-# Byte-compiled / optimized / DLL files
-__pycache__/
-*.py[cod]
-*$py.class
-
-# C extensions
-*.so
-
-# Distribution / packaging
-.Python
-build/
-develop-eggs/
-dist/
-downloads/
-eggs/
-.eggs/
-lib/
-lib64/
-parts/
-sdist/
-var/
-wheels/
-pip-wheel-metadata/
-share/python-wheels/
-*.egg-info/
-.installed.cfg
-*.egg
-MANIFEST
-
-# PyInstaller
-#  Usually these files are written by a python script from a template
-#  before PyInstaller builds the exe, so as to inject date/other infos into it.
-*.manifest
-*.spec
-
-# Installer logs
-pip-log.txt
-pip-delete-this-directory.txt
-
-# Unit test / coverage reports
-htmlcov/
-.tox/
-.nox/
-.coverage
-.coverage.*
-.cache
-nosetests.xml
-coverage.xml
-*.cover
-*.py,cover
-.hypothesis/
-.pytest_cache/
-
-# Translations
-*.mo
-*.pot
-
-# Django stuff:
-*.log
-local_settings.py
-db.sqlite3
-db.sqlite3-journal
-
-# Flask stuff:
-instance/
-.webassets-cache
-
-# Scrapy stuff:
-.scrapy
-
-# Sphinx documentation
-docs/_build/
-
-# PyBuilder
-target/
-
-# Jupyter Notebook
-.ipynb_checkpoints
-
-# IPython
-profile_default/
-ipython_config.py
-
-# pyenv
-.python-version
-
-# pipenv
-#   According to pypa/pipenv#598, it is recommended to include Pipfile.lock in version control.
-#   However, in case of collaboration, if having platform-specific dependencies or dependencies
-#   having no cross-platform support, pipenv may install dependencies that don't work, or not
-#   install all needed dependencies.
-#Pipfile.lock
-
-# PEP 582; used by e.g. github.com/David-OConnor/pyflow
-__pypackages__/
-
-# Celery stuff
-celerybeat-schedule
-celerybeat.pid
-
-# SageMath parsed files
-*.sage.py
-
-# Environments
-.env
-.venv
-env/
-venv/
-ENV/
-env.bak/
-venv.bak/
-
-# Spyder project settings
-.spyderproject
-.spyproject
-
-# Rope project settings
-.ropeproject
-
-# mkdocs documentation
-/site
-
-# mypy
 .mypy_cache/
-.dmypy.json
-dmypy.json
-
-# Pyre type checker
-.pyre/
+/.coverage
+/.coverage.*
+/.nox/
+/.python-version
+/.pytype/
+/dist/
+/docs/_build/
+/src/*.egg-info/
+__pycache__/
diff --git a/README.md b/README.md
index 6377694..cdcaf4b 100644
--- a/README.md
+++ b/README.md
@@ -4,7 +4,7 @@ Diagrams as text tools for databases and distributed systems
 
 [_ophistory_](#ophistory) lets you write a simple text file of operations starting and ending in order, and renders them like so:[^1]
 
-<img src="examples/ophistory_all.svg" />
+<img src="docs/ophistory_all.svg" />
 
 ## ophistory
 
@@ -41,7 +41,7 @@ A: D(y)
 A: E(z)
 </code></pre>
   </td>
-  <td><img src="examples/linearizability_1.2.a.svg" /></td>
+  <td><img src="docs/linearizability_1.2.a.svg" /></td>
 </tr>
   <td>
 <pre><code>
@@ -52,7 +52,7 @@ B: END a
 A: END a
 </code></pre>
   </td>
-  <td><img src="examples/linearizability_1.2.b.svg" /></td>
+  <td><img src="docs/linearizability_1.2.b.svg" /></td>
 </tr>
   <td>
 <pre><code>
@@ -61,7 +61,7 @@ B: D(x)
 A: END a
 </code></pre>
   </td>
-  <td><img src="examples/linearizability_1.2.c.svg" /></td>
+  <td><img src="docs/linearizability_1.2.c.svg" /></td>
 </tr>
   <td>
 <pre><code>
@@ -75,7 +75,7 @@ A: END a
 C: END a
 </code></pre>
   </td>
-  <td><img src="examples/linearizability_1.2.d.svg" /></td>
+  <td><img src="docs/linearizability_1.2.d.svg" /></td>
 </tr>
 </tbody>
 </table>
diff --git a/examples/linearizability_1.2.a.svg b/docs/linearizability_1.2.a.svg
similarity index 100%
rename from examples/linearizability_1.2.a.svg
rename to docs/linearizability_1.2.a.svg
diff --git a/examples/linearizability_1.2.b.svg b/docs/linearizability_1.2.b.svg
similarity index 100%
rename from examples/linearizability_1.2.b.svg
rename to docs/linearizability_1.2.b.svg
diff --git a/examples/linearizability_1.2.c.svg b/docs/linearizability_1.2.c.svg
similarity index 100%
rename from examples/linearizability_1.2.c.svg
rename to docs/linearizability_1.2.c.svg
diff --git a/examples/linearizability_1.2.d.svg b/docs/linearizability_1.2.d.svg
similarity index 100%
rename from examples/linearizability_1.2.d.svg
rename to docs/linearizability_1.2.d.svg
diff --git a/examples/ophistory_all.svg b/docs/ophistory_all.svg
similarity index 100%
rename from examples/ophistory_all.svg
rename to docs/ophistory_all.svg
diff --git a/examples/ophistory_all.txt b/docs/ophistory_all.txt
similarity index 100%
rename from examples/ophistory_all.txt
rename to docs/ophistory_all.txt
diff --git a/ophistory.py b/src/ophistory.py
similarity index 100%
rename from ophistory.py
rename to src/ophistory.py
index c59fcd4..a4d35a2 100755
--- a/ophistory.py
+++ b/src/ophistory.py
@@ -75,19 +75,6 @@ def parse_operations(text : str) -> list[Operation]:
 
 #### Data Model
 
-@dataclasses.dataclass
-class Span(object):
-    actor : str
-    start : int
-    end : int
-    height : int
-    text : tuple[Optional[str], Optional[str]]
-    eventpoint : Optional[int]
-    x1 : Optional[UnitsCh] = None
-    x2 : Optional[UnitsCh] = None
-    event_x : Optional[UnitsCh] = None
-    y : Optional[UnitsPx] = None
-
 class TokenBucket(object):
     def __init__(self):
         self._tokens = []
@@ -108,6 +95,19 @@ def release(self, token : int) -> None:
     def max_token(self) -> int:
         return self._max_token
 
+@dataclasses.dataclass
+class Span(object):
+    actor : str
+    start : int
+    end : int
+    height : int
+    text : tuple[Optional[str], Optional[str]]
+    eventpoint : Optional[int]
+    x1 : Optional[UnitsCh] = None
+    x2 : Optional[UnitsCh] = None
+    event_x : Optional[UnitsCh] = None
+    y : Optional[UnitsPx] = None
+
 @dataclasses.dataclass
 class SpanStart(object):
     op : str