diff --git a/packages/squiggle-lang/__tests__/Symbolic_test.res b/packages/squiggle-lang/__tests__/Symbolic_test.res
index bac4d17b..8ec3be22 100644
--- a/packages/squiggle-lang/__tests__/Symbolic_test.res
+++ b/packages/squiggle-lang/__tests__/Symbolic_test.res
@@ -22,13 +22,12 @@ describe("Normal distribution with sparklines", () => {
 
   let normalDistAtMean5: SymbolicDistTypes.normal = {mean: 5.0, stdev: 2.0}
   let normalDistAtMean10: SymbolicDistTypes.normal = {mean: 10.0, stdev: 2.0}
-  let range20Float = E.A.rangeFloat(0, 20) // [0.0,1.0,2.0,3.0,4.0,5.0,6.0,7.0,8.0,9.0,10.0,11.0,12.0,13.0,14.0,15.0,16.0,17.0,18.0,19.0,]
+  let range20Float = E.A.rangeFloat(0, 20) // [0.0,1.0,2.0,3.0,4.0,...19.0,]
 
   let pdfNormalDistAtMean5 = x => Normal.pdf(x, normalDistAtMean5)
   let sparklineMean5 = pdfImage(pdfNormalDistAtMean5, range20Float)
   makeTest("mean=5", Sparklines.create(sparklineMean5, ()), `▁▂▃▅███▅▃▂▁▁▁▁▁▁▁▁▁▁▁`)
 
   let sparklineMean15 = normalDistAtMean5 -> parameterWiseAdditionHelper(normalDistAtMean10) -> pdfImage(range20Float)
-  // let sparklineMean15 = pdfImage(pdfNormalDistAtMean15, range20Float)
   makeTest("parameter-wise addition of two normal distributions", Sparklines.create(sparklineMean15, ()), `▁▁▁▁▁▁▁▁▁▁▂▃▅▇███▇▅▃▂`)
 })
diff --git a/packages/squiggle-lang/src/rescript/utility/E.res b/packages/squiggle-lang/src/rescript/utility/E.res
index eb366a6d..6d2a2ce2 100644
--- a/packages/squiggle-lang/src/rescript/utility/E.res
+++ b/packages/squiggle-lang/src/rescript/utility/E.res
@@ -269,7 +269,8 @@ module A = {
       ))
       |> Rationale.Result.return
     }
-  let rangeFloat = (start, stop) => start -> Belt.Array.rangeBy(stop, ~step=1) -> (arr => fmap(Belt.Int.toFloat, arr))
+  let rangeFloat = (~step=1, start, stop) =>
+    Belt.Array.rangeBy(start, stop, ~step) |> fmap(Belt.Int.toFloat)
 
   // This zips while taking the longest elements of each array.
   let zipMaxLength = (array1, array2) => {
@@ -324,7 +325,7 @@ module A = {
         }
     )
   let filter = (o, e) => Js.Array.filter(o, e)
-  let joinWith = (fill, arr) => Js.Array.joinWith(fill, arr)
+  let joinWith = Js.Array.joinWith
 
   module O = {
     let concatSomes = (optionals: array<option<'a>>): array<'a> =>
@@ -407,6 +408,7 @@ module A = {
             : {
                 let _ = Js.Array.push(element, continuous)
               }
+
           ()
         })
 
diff --git a/packages/squiggle-lang/src/rescript/utility/Sparklines.res b/packages/squiggle-lang/src/rescript/utility/Sparklines.res
index 09e17e37..cc07860f 100644
--- a/packages/squiggle-lang/src/rescript/utility/Sparklines.res
+++ b/packages/squiggle-lang/src/rescript/utility/Sparklines.res
@@ -3,26 +3,24 @@
 // Omitting rgb "fire" style, so no `chalk` dependency
 // Omitting: NaN handling, special consideration for constant data.
 
-let create = (
-  numbers: array<float>,
-  ~minimum=?,
-  ~maximum=?,
-  ()
-) => {
-  let ticks = [`▁`, `▂`, `▃`, `▄`, `▅`, `▆`, `▇`, `█`]
+let ticks = [`▁`, `▂`, `▃`, `▄`, `▅`, `▆`, `▇`, `█`]
 
-  let minimum = E.O.default(Js.Math.minMany_float(numbers), minimum)
-  let maximum = E.O.default(Js.Math.maxMany_float(numbers), maximum)
+let _ticksLength = E.A.length(ticks)
 
-  let toHeight = (number: float) => {
-    let tickIndex = Js.Math.ceil_int((number /. maximum) *. (ticks -> Belt.Array.length -> Belt.Int.toFloat)) - 1
-    let tickIndex = if maximum == 0.0 || tickIndex < 0 {
-        0
-      } else {
-        tickIndex
-      }
-    ticks[tickIndex]
-  }
-
-  toHeight -> E.A.fmap(numbers) -> (arr => E.A.joinWith("", arr))
+let _heightToTickIndex = (maximum: float, v: float) => {
+  let v = Js.Math.ceil_int(v /. maximum *. Belt.Int.toFloat(_ticksLength)) - 1
+  min(v, 0)
+}
+
+let create = (relativeHeights: array<float>, ~maximum=?, ()) => {
+  if E.A.length(relativeHeights) === 0 {
+    ""
+  } else {
+    let maximum = maximum |> E.O.default(E.A.max(relativeHeights) |> E.O.toExn(""))
+
+    relativeHeights
+    |> E.A.fmap(_heightToTickIndex(maximum))
+    |> E.A.fmap(r => E.A.get(ticks, r) |> E.O.toExn(""))
+    |> E.A.joinWith("")
+  }
 }