diff --git a/crates/post/scripts/inverter_characteristics.py b/crates/post/scripts/inverter_characteristics.py
new file mode 100755
index 0000000..a29d871
--- /dev/null
+++ b/crates/post/scripts/inverter_characteristics.py
@@ -0,0 +1,141 @@
+#!/usr/bin/env python3
+import plotly.express as px
+from pandas import DataFrame
+
+# df = pd.DataFrame(data=dict(x=[1, 2, 3, 4], y=[1, 4, 9, 16]))
+# fig = px.line(df, x="x", y="y", title="test")
+# fig.show()
+
+class Line:
+    def __init__(self, from_, to):
+        self.from_ = from_
+        self.to = to
+
+    def slope(self) -> float:
+        return (self.to[1] - self.from_[1]) / (self.to[0] - self.from_[0])
+
+    def get(self, x: float) -> float:
+        from_x, from_y = self.from_
+        to_x, to_y = self.to
+        tween = (x - from_x) / (to_x - from_x)
+        return tween * to_y + (1-tween) * from_y
+
+
+class Piecewise:
+    def __init__(self, xy: list):
+        """ xy is a list of (x, y) pairs """
+        self.xy = list(xy)
+
+    def normalized(self, prev_max: float) -> 'Piecewise':
+        """ map every coordinate from [-prev_max, prev_max] to [0, 1] """
+        p = prev_max
+        r = 2*prev_max
+        s = 1.0/r
+        return Piecewise([
+            (s*(x + p), s*(y + p)) for (x, y) in self.xy
+        ])
+
+    def logically_inverted(self) -> 'Piecewise':
+        """ return a Piecewise that evaluates to 1-y """
+        return Piecewise([
+            (x, 1-y) for (x, y) in self.xy
+        ])
+
+    def line_for(self, x: float) -> Line:
+        for first_lower in self.xy[:-1][::-1]:
+            if first_lower[0] < x: break
+        for first_upper in self.xy[1:]:
+            if first_upper[0] > x: break
+
+        return Line(first_lower, first_upper)
+
+    def get(self, x: float) -> float:
+        """
+        evaluate the piecewise function at the provided x value.
+        OOB points are just extrapolated from the nearest piece.
+        """
+        return self.line_for(x).get(x)
+
+    def get_slope(self, x: float) -> float:
+        return self.line_for(x).slope()
+
+    def get_repeated(self, x: float, n: int = 63) -> float:
+        for _ in range(n):
+            x = self.get(x)
+        return x
+
+    def df_for(self, from_: float, to: float, points: int, f) -> DataFrame:
+        x_step = (to - from_) / (points - 1)
+        x = [from_ + x_step*x for x in range(points)]
+        y = [f(xi) for xi in x]
+        return DataFrame(data=dict(x=x, y=y))
+
+    def df(self, from_: float = 0.0, to: float = 1.0, points: int = 101) -> DataFrame:
+        return self.df_for(from_, to, points, self.get)
+
+    def slope_df(self, from_: float = 0.0, to: float = 1.0, points: int = 101) -> DataFrame:
+        return self.df_for(from_, to, points, self.get_slope)
+
+    def plot_for(self, from_: float, to: float, title: str, f):
+        df = self.df_for(from_, to, points=101, f=f)
+        fig = px.line(df, x="x", y="y", title=title)
+        fig.show()
+
+    def plot(self, from_: float = 0.0, to: float = 1.0, title: str = "Piecewise"):
+        self.plot_for(from_, to, title, self.get)
+
+    def plot_slope(self, from_: float = 0.0, to: float = 1.0, title: str = "Piecewise"):
+        self.plot_for(from_, to, title, self.get_slope)
+
+    def plot_equilibrium(self, from_: float = 0.0, to: float = 1.0, title: str = "Piecewise"):
+        self.plot_for(from_, to, title, self.get_repeated)
+
+
+fwd_26 = Piecewise(
+    [
+        [ -14687, -7326 ],
+        [ -13049, -6503 ],
+        [ -11785, -5833 ],
+        [ -4649,  -1447 ],
+        [ 4961,    7059 ],
+        [ 11283,  11147 ],
+    ]
+).normalized(17000)
+
+# fwd_26.plot(title = "26 forward")
+# fwd_26.logically_inverted().plot(title = "26 inverted")
+# fwd_26.plot_slope(title = "26 slope")
+# fwd_26.logically_inverted().plot_equilibrium(title = "26 equilibrium")
+
+
+fwd_38_2_0 = Piecewise(
+    [
+        [ (-13745 + -13012)/2, -6222 ],
+        [ (-4969 + -4744)/2,    2373 ],
+        [ (1772 + 2070)/2,     10467 ],
+        [ (4472 + 4114)/2,     12921 ],
+        [ (7221 + 6291)/2,     14530 ],
+        [ (11159 + 10397)/2,   15865 ],
+        [ (12430 + 15653)/2,   16202 ],
+    ]
+).normalized(17000)
+fwd_38_2_0.plot(title = "38 2:0 forward")
+fwd_38_2_0.logically_inverted().plot(title = "38 2:0 inverted")
+fwd_38_2_0.plot_slope(title = "38 2:0 slope")
+fwd_38_2_0.logically_inverted().plot_equilibrium(title = "38 2:0 equilibrium")
+
+fwd_38_3_0 = Piecewise(
+    [
+        [ (-13956 + -13890 + -13077)/3, -5203],
+        [ (-4979 + -4885  + -4717)/3, 5051],
+        [ (1531 + 503 + 1006)/3, 12509],
+        [ (4180 + 1821 + 2239)/3, 14386],
+        [ (6986 + 3436 + 3701)/3, 15451],
+        [ (10482 + 6644 + 7735)/3, 16081],
+        [ (11436 + 13343 + 14411)/3, 16380],
+    ]
+).normalized(17000)
+fwd_38_3_0.plot(title = "38 3:0 forward")
+fwd_38_3_0.logically_inverted().plot(title = "38 3:0 inverted")
+fwd_38_3_0.plot_slope(title = "38 3:0 slope")
+fwd_38_3_0.logically_inverted().plot_equilibrium(title = "38 3:0 equilibrium")
diff --git a/flake.nix b/flake.nix
index 774bef9..262089d 100644
--- a/flake.nix
+++ b/flake.nix
@@ -14,6 +14,11 @@
         overlays = [ rust-overlay.overlays.default ];
       };
       rust-toolchain = pkgs.rust-bin.fromRustupToolchainFile ./rust-toolchain.toml;
+      python-packages = pypkg: with pypkg; [
+        pandas
+        plotly
+      ];
+      python3 = pkgs.python3.withPackages python-packages;
     in
     rec {
       packages = {
@@ -51,7 +56,7 @@
         # Allow cargo to download crates.
         SSL_CERT_FILE = "${cacert}/etc/ssl/certs/ca-bundle.crt";
 
-        buildInputs = [ rust-toolchain ];
+        buildInputs = [ rust-toolchain python3 ];
 
         # Runtime dependencies.
         LD_LIBRARY_PATH = lib.makeLibraryPath [ pkgs.vulkan-loader ];