diff --git a/src/components/DistBuilder.re b/src/components/DistBuilder.re
index e1213eec..28510795 100644
--- a/src/components/DistBuilder.re
+++ b/src/components/DistBuilder.re
@@ -197,7 +197,7 @@ module DemoDist = {
                   )
                |> E.A.R.firstErrorOrOpen;
              switch (results) {
-             | Ok(dists) => <> <PercentilesChart dists /> </>
+             | Ok(dists) => <PercentilesChart dists />
              | Error(r) => r |> R.ste
              };
            | Error(r) => r |> R.ste
@@ -211,6 +211,18 @@ module DemoDist = {
   };
 };
 
+//         guesstimatorString: "
+//         us_economy_2018 = (10.5 to 10.6)T
+// growth_rate = 1.08 to 1.2
+// us_economy(t) = us_economy_2018 * (growth_rate^t)
+
+// us_population_2019 = 320M to 330M
+// us_population_growth_rate = 1.01 to 1.02
+// us_population(t) = us_population_2019 * (us_population_growth_rate^t)
+
+// gdp_per_person(t) = us_economy(t)/us_population(t)
+// gdp_per_person
+// ",
 [@react.component]
 let make = () => {
   let (reloader, setReloader) = React.useState(() => 1);
@@ -221,18 +233,7 @@ let make = () => {
       ~onSubmit=({state}) => {None},
       ~initialState={
         //guesstimatorString: "mm(normal(-10, 2), uniform(18, 25), lognormal({mean: 10, stdev: 8}), triangular(31,40,50))",
-        guesstimatorString: "
-        us_economy_2018 = (10.5 to 10.6)T
-growth_rate = 1.08 to 1.2
-us_economy(t) = us_economy_2018 * (growth_rate^t)
-
-us_population_2019 = 320M to 330M
-us_population_growth_rate = 1.01 to 1.02
-us_population(t) = us_population_2019 * (us_population_growth_rate^t)
-
-gdp_per_person(t) = us_economy(t)/us_population(t)
-gdp_per_person
-",
+         guesstimatorString: "mm(3,4)",
         domainType: "Complete",
         xPoint: "50.0",
         xPoint2: "60.0",
diff --git a/src/distPlus/expressionTree/ExpressionTreeEvaluator.re b/src/distPlus/expressionTree/ExpressionTreeEvaluator.re
index f75254ff..4a650870 100644
--- a/src/distPlus/expressionTree/ExpressionTreeEvaluator.re
+++ b/src/distPlus/expressionTree/ExpressionTreeEvaluator.re
@@ -254,6 +254,7 @@ let rec toLeaf =
           node: t,
         )
         : result(t, string) => {
+          Js.log2("node",node);
   switch (node) {
   // Leaf nodes just stay leaf nodes
   | `SymbolicDist(_)
diff --git a/src/distPlus/expressionTree/Fns.re b/src/distPlus/expressionTree/Fns.re
index af7a28e4..cbaf375b 100644
--- a/src/distPlus/expressionTree/Fns.re
+++ b/src/distPlus/expressionTree/Fns.re
@@ -1,7 +1,6 @@
 open TypeSystem;
 
 let wrongInputsError = r => {
-  Js.log2("Wrong inputs", r);
   Error("Wrong inputs");
 };
 
@@ -18,8 +17,8 @@ let to_: (float, float) => result(node, string) =
 let makeSymbolicFromTwoFloats = (name, fn) =>
   Function.make(
     ~name,
-    ~output=`SamplingDistribution,
-    ~inputs=[|`Float, `Float|],
+    ~outputType=`SamplingDistribution,
+    ~inputTypes=[|`Float, `Float|],
     ~run=
       fun
       | [|`Float(a), `Float(b)|] => Ok(`SymbolicDist(fn(a, b)))
@@ -29,8 +28,8 @@ let makeSymbolicFromTwoFloats = (name, fn) =>
 let makeSymbolicFromOneFloat = (name, fn) =>
   Function.make(
     ~name,
-    ~output=`SamplingDistribution,
-    ~inputs=[|`Float|],
+    ~outputType=`SamplingDistribution,
+    ~inputTypes=[|`Float|],
     ~run=
       fun
       | [|`Float(a)|] => Ok(`SymbolicDist(fn(a)))
@@ -40,8 +39,8 @@ let makeSymbolicFromOneFloat = (name, fn) =>
 let makeDistFloat = (name, fn) =>
   Function.make(
     ~name,
-    ~output=`SamplingDistribution,
-    ~inputs=[|`SamplingDistribution, `Float|],
+    ~outputType=`SamplingDistribution,
+    ~inputTypes=[|`SamplingDistribution, `Float|],
     ~run=
       fun
       | [|`SamplingDist(a), `Float(b)|] => fn(a, b)
@@ -51,19 +50,19 @@ let makeDistFloat = (name, fn) =>
 let makeRenderedDistFloat = (name, fn) =>
   Function.make(
     ~name,
-    ~output=`RenderedDistribution,
-    ~inputs=[|`RenderedDistribution, `Float|],
+    ~outputType=`RenderedDistribution,
+    ~inputTypes=[|`RenderedDistribution, `Float|],
     ~run=
       fun
       | [|`RenderedDist(a), `Float(b)|] => fn(a, b)
-      | e => wrongInputsError(e),
+      | e => wrongInputsError(e)
   );
 
 let makeDist = (name, fn) =>
   Function.make(
     ~name,
-    ~output=`SamplingDistribution,
-    ~inputs=[|`SamplingDistribution|],
+    ~outputType=`SamplingDistribution,
+    ~inputTypes=[|`SamplingDistribution|],
     ~run=
       fun
       | [|`SamplingDist(a)|] => fn(a)
@@ -115,8 +114,8 @@ let functions = [|
   makeSymbolicFromOneFloat("exponential", SymbolicDist.Exponential.make),
   Function.make(
     ~name="to",
-    ~output=`SamplingDistribution,
-    ~inputs=[|`Float, `Float|],
+    ~outputType=`SamplingDistribution,
+    ~inputTypes=[|`Float, `Float|],
     ~run=
       fun
       | [|`Float(a), `Float(b)|] => to_(a, b)
@@ -124,8 +123,8 @@ let functions = [|
   ),
   Function.make(
     ~name="triangular",
-    ~output=`SamplingDistribution,
-    ~inputs=[|`Float, `Float, `Float|],
+    ~outputType=`SamplingDistribution,
+    ~inputTypes=[|`Float, `Float, `Float|],
     ~run=
       fun
       | [|`Float(a), `Float(b), `Float(c)|] =>
@@ -140,8 +139,8 @@ let functions = [|
   makeDist("sample", dist => floatFromDist(`Sample, dist)),
   Function.make(
     ~name="render",
-    ~output=`RenderedDistribution,
-    ~inputs=[|`RenderedDistribution|],
+    ~outputType=`RenderedDistribution,
+    ~inputTypes=[|`RenderedDistribution|],
     ~run=
       fun
       | [|`RenderedDist(c)|] => Ok(`RenderedDist(c))
@@ -149,8 +148,8 @@ let functions = [|
   ),
   Function.make(
     ~name="normalize",
-    ~output=`SamplingDistribution,
-    ~inputs=[|`SamplingDistribution|],
+    ~outputType=`SamplingDistribution,
+    ~inputTypes=[|`SamplingDistribution|],
     ~run=
       fun
       | [|`SamplingDist(`SymbolicDist(c))|] => Ok(`SymbolicDist(c))
diff --git a/src/distPlus/expressionTree/Functions.re b/src/distPlus/expressionTree/Functions.re
index eb127918..a99581ce 100644
--- a/src/distPlus/expressionTree/Functions.re
+++ b/src/distPlus/expressionTree/Functions.re
@@ -38,7 +38,13 @@ let fnn =
              });
         Ok(`MultiModal(withWeights));
       | dists when E.L.length(dists) > 0 =>
-        Ok(`MultiModal(dists |> E.L.toArray |> E.A.fmap(r => (r, 1.0))))
+        Ok(
+          `MultiModal(
+            dists
+            |> E.L.toArray
+            |> E.A.fmap(r => (r, 1.0)),
+          ),
+        )
       | _ => Error("Needs at least one distribution")
       }
     | _ => Error("Function " ++ name ++ " not found")
diff --git a/src/distPlus/expressionTree/TypeSystem.re b/src/distPlus/expressionTree/TypeSystem.re
index d13e62d6..0ecc070e 100644
--- a/src/distPlus/expressionTree/TypeSystem.re
+++ b/src/distPlus/expressionTree/TypeSystem.re
@@ -20,24 +20,25 @@ type tx = [
   | `Array(array(tx))
   | `Named(array((string, tx)))
 ];
+
 type fn = {
   name: string,
-  inputs: array(t),
-  output: t,
+  inputTypes: array(t),
+  outputType: t,
   run: array(tx) => result(node, string),
 };
 
 module Function = {
-  let make = (~name, ~inputs, ~output, ~run): fn => {
+  let make = (~name, ~inputTypes, ~outputType, ~run): fn => {
     name,
-    inputs,
-    output,
+    inputTypes,
+    outputType,
     run,
   };
 };
 
 type fns = array(fn);
-type inputs = array(node);
+type inputTypes = array(node);
 
 let rec fromNodeDirect = (node: node): result(tx, string) =>
   switch (ExpressionTypes.ExpressionTree.toFloatIfNeeded(node)) {
@@ -64,10 +65,7 @@ let compareInput = (evaluationParams, t: t, node) =>
   | `Float =>
     switch (getFloat(node)) {
     | Some(a) => Ok(`Float(a))
-    | _ =>
-      Error(
-        "Type Error: Expected float."
-      )
+    | _ => Error("Type Error: Expected float.")
     }
   | `SamplingDistribution =>
     PTypes.SamplingDistribution.renderIfIsNotSamplingDistribution(
@@ -78,50 +76,57 @@ let compareInput = (evaluationParams, t: t, node) =>
   | `RenderedDistribution =>
     ExpressionTypes.ExpressionTree.Render.render(evaluationParams, node)
     |> E.R.bind(_, fromNodeDirect)
-  | _ => Error("Bad input, sorry.")
+  | _ => {
+    Js.log4("Type error: Expected ", t, ", got ", node);
+    Error("Bad input, sorry.")}
   };
 
 let sanatizeInputs =
     (
       evaluationParams: ExpressionTypes.ExpressionTree.evaluationParams,
-      inputs: inputs,
+      inputTypes: inputTypes,
       t: fn,
     ) => {
-  E.A.length(t.inputs) == E.A.length(inputs)
-    ? Belt.Array.zip(t.inputs, inputs)
+  E.A.length(t.inputTypes) == E.A.length(inputTypes)
+    ? Belt.Array.zip(t.inputTypes, inputTypes)
       |> E.A.fmap(((def, input)) =>
            compareInput(evaluationParams, def, input)
          )
+         |> (r => {Js.log2("Inputs", r); r})
       |> E.A.R.firstErrorOrOpen
     : Error(
         "Wrong number of inputs. Expected"
-        ++ (E.A.length(t.inputs) |> E.I.toString)
+        ++ (E.A.length(t.inputTypes) |> E.I.toString)
         ++ ". Got:"
-        ++ (E.A.length(inputs) |> E.I.toString),
+        ++ (E.A.length(inputTypes) |> E.I.toString),
       );
 };
 
 let run =
     (
       evaluationParams: ExpressionTypes.ExpressionTree.evaluationParams,
-      inputs: inputs,
+      inputTypes: inputTypes,
       t: fn,
-    ) =>{
-  (
-    switch (sanatizeInputs(evaluationParams, inputs, t)) {
-    | Ok(inputs) => t.run(inputs)
-    | Error(r) => Error(r)
-    }
-  )
+    ) => {
+  let _sanitizedInputs = sanatizeInputs(evaluationParams, inputTypes, t);
+  _sanitizedInputs |> E.R.bind(_,t.run)
   |> (
     fun
     | Ok(i) => Ok(i)
-    | Error(r) => {Js.log4("Error", inputs, t, sanatizeInputs(evaluationParams, inputs, t), ); Error("Function " ++ t.name ++ " error: " ++ r)}
+    | Error(r) => {
+        Js.log4(
+          "Error",
+          inputTypes,
+          t,
+          _sanitizedInputs
+        );
+        Error("Function " ++ t.name ++ " error: " ++ r);
+      }
   );
-    }
+};
 
 let getFn = (fns: fns, n: string) =>
   fns |> Belt.Array.getBy(_, ({name}) => name == n);
 
-let getAndRun = (fns: fns, n: string, evaluationParams, inputs) =>
-  getFn(fns, n) |> E.O.fmap(run(evaluationParams, inputs));
+let getAndRun = (fns: fns, n: string, evaluationParams, inputTypes) =>
+  getFn(fns, n) |> E.O.fmap(run(evaluationParams, inputTypes));