diff --git a/packages/core/euclid.mjs b/packages/core/euclid.mjs
index 25e12b07c..44ab07f11 100644
--- a/packages/core/euclid.mjs
+++ b/packages/core/euclid.mjs
@@ -10,7 +10,7 @@ https://rohandrape.net/?t=hmt
 This program is free software: you can redistribute it and/or modify it under the terms of the GNU Affero General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Affero General Public License for more details. You should have received a copy of the GNU Affero General Public License along with this program.  If not, see <https://www.gnu.org/licenses/>.
 */
 
-import { timeCat, register, silence } from './pattern.mjs';
+import { timeCat, register, silence, stack, pure, _morph } from './pattern.mjs';
 import { rotate, flatten, splitAt, zipWith } from './util.mjs';
 import Fraction, { lcm } from './fraction.mjs';
 
@@ -196,3 +196,26 @@ export const euclidLegato = register(['euclidLegato'], function (pulses, steps,
 export const euclidLegatoRot = register(['euclidLegatoRot'], function (pulses, steps, rotation, pat) {
   return _euclidLegato(pulses, steps, rotation, pat);
 });
+
+/**
+ * A 'euclid' variant with an additional parameter that morphs the resulting
+ * rhythm from 0 (no morphing) to 1 (completely 'even'). For example
+ * `sound("bd").euclidish(3,8,0)` would be the same as
+ * `sound("bd").euclid(3,8)`, and `sound("bd").euclidish(3,8,1)` would be the
+ * same as `sound("bd bd bd")`. `sound("bd").euclidish(3,8,0.5)` would have a
+ * groove somewhere between.
+ * Inspired by the work of Malcom Braff.
+ * @name euclidish
+ * @synonyms eish
+ * @memberof Pattern
+ * @param {number} pulses the number of onsets
+ * @param {number} steps the number of steps to fill
+ * @param {number} groove exists between the extremes of 0 (straight euclidian) and 1 (straight pulse)
+ * @example
+ * sound("hh").euclidish(7,12,sine.slow(8))
+ * .pan(sine.slow(8))
+ */
+export const { euclidish, eish } = register(['euclidish', 'eish'], function (pulses, steps, perc, pat) {
+  const morphed = _morph(bjork(pulses, steps), new Array(pulses).fill(1), perc);
+  return pat.struct(morphed).setSteps(steps);
+});
diff --git a/packages/core/pattern.mjs b/packages/core/pattern.mjs
index dbf1b17f7..f1ebbe3e9 100644
--- a/packages/core/pattern.mjs
+++ b/packages/core/pattern.mjs
@@ -21,6 +21,7 @@ import {
   numeralArgs,
   parseNumeral,
   pairs,
+  zipWith,
   stringifyValues,
 } from './util.mjs';
 import drawLine from './drawLine.mjs';
@@ -3416,3 +3417,69 @@ export const { beat } = register(
   ['beat'],
   __beat((x) => x.innerJoin()),
 );
+
+export const _morph = (from, to, by) => {
+  by = Fraction(by);
+  const dur = Fraction(1).div(from.length);
+  const positions = (list) => {
+    const result = [];
+    for (const [pos, value] of list.entries()) {
+      if (value) {
+        result.push([Fraction(pos).div(list.length), value]);
+      }
+    }
+    return result;
+  };
+  const arcs = zipWith(
+    ([posa, valuea], [posb, valueb]) => {
+      const b = by.mul(posb - posa).add(posa);
+      const e = b.add(dur);
+      return new TimeSpan(b, e);
+    },
+    positions(from),
+    positions(to),
+  );
+  function query(state) {
+    const cycle = state.span.begin.sam();
+    const cycleArc = state.span.cycleArc();
+    const result = [];
+    for (const whole of arcs) {
+      const part = whole.intersection(cycleArc);
+      if (part !== undefined) {
+        result.push(
+          new Hap(
+            whole.withTime((x) => x.add(cycle)),
+            part.withTime((x) => x.add(cycle)),
+            true,
+          ),
+        );
+      }
+    }
+    return result;
+  }
+  return new Pattern(query).splitQueries();
+};
+
+/**
+ * Takes two binary rhythms represented as lists of 1s and 0s, and a number
+ * between 0 and 1 that morphs between them. The two lists should contain the same
+ * number of true values.
+ * @example
+ * sound("hh").struct(morph([1,0,1,0,1,0,1,0], // straight rhythm
+ *                          [1,1,0,1,0,1,0], // wonky rhythm
+ *                          0.25 // creates a slightly wonky rhythm
+ *                         )
+ *                   )
+ * @example
+ * sound("hh").struct(morph("1:0:1:0:1:0:1:0", // straight rhythm
+ *                          "1:1:0:1:0:1:0", // wonky rhythm
+ *                          sine.slow(8) // slowly morph between the rhythms
+ *                         )
+ *                   )
+ */
+export const morph = (frompat, topat, bypat) => {
+  frompat = reify(frompat);
+  topat = reify(topat);
+  bypat = reify(bypat);
+  return frompat.innerBind((from) => topat.innerBind((to) => bypat.innerBind((by) => _morph(from, to, by))));
+};
diff --git a/packages/core/timespan.mjs b/packages/core/timespan.mjs
index 0dbc74fc8..446156bbf 100644
--- a/packages/core/timespan.mjs
+++ b/packages/core/timespan.mjs
@@ -72,7 +72,7 @@ export class TimeSpan {
   }
 
   intersection(other) {
-    // Intersection of two timespans, returns None if they don't intersect.
+    // Intersection of two timespans, returns undefined if they don't intersect.
     const intersect_begin = this.begin.max(other.begin);
     const intersect_end = this.end.min(other.end);
 
diff --git a/test/__snapshots__/examples.test.mjs.snap b/test/__snapshots__/examples.test.mjs.snap
index bb0489a91..398749359 100644
--- a/test/__snapshots__/examples.test.mjs.snap
+++ b/test/__snapshots__/examples.test.mjs.snap
@@ -3410,6 +3410,39 @@ exports[`runs examples > example "euclidRot" example index 0 1`] = `
 ]
 `;
 
+exports[`runs examples > example "euclidish" example index 0 1`] = `
+[
+  "[ 0/1 → 1/12 | s:hh pan:0.5 ]",
+  "[ 13/84 → 5/21 | s:hh pan:0.5606253170575308 ]",
+  "[ 15/56 → 59/168 | s:hh pan:0.604413082836085 ]",
+  "[ 71/168 → 85/168 | s:hh pan:0.6629314122869361 ]",
+  "[ 97/168 → 37/56 | s:hh pan:0.7190455010067492 ]",
+  "[ 29/42 → 65/84 | s:hh pan:0.7580531369037533 ]",
+  "[ 71/84 → 13/14 | s:hh pan:0.8080762739548087 ]",
+  "[ 1/1 → 13/12 | s:hh pan:0.8535533905932737 ]",
+  "[ 451099417/393511398 → 322594689/262340932 | s:hh pan:0.891768001805729 ]",
+  "[ 335923379/262340932 → 536677685/393511398 | s:hh pan:0.9222657853371297 ]",
+  "[ 1122946175/787022796 → 99044284/65585233 | s:hh pan:0.9501869591788796 ]",
+  "[ 1238122213/787022796 → 651853723/393511398 | s:hh pan:0.9721673436944069 ]",
+  "[ 335923379/196755699 → 469759583/262340932 | s:hh pan:0.9868472639237561 ]",
+  "[ 729434777/393511398 → 1524454787/787022796 | s:hh pan:0.9967009321321423 ]",
+  "[ 2/1 → 25/12 | s:hh pan:1 ]",
+  "[ 15/7 → 187/84 | s:hh pan:0.9968561049466214 ]",
+  "[ 16/7 → 199/84 | s:hh pan:0.9874639560909118 ]",
+  "[ 17/7 → 211/84 | s:hh pan:0.9719416651541839 ]",
+  "[ 18/7 → 223/84 | s:hh pan:0.9504844339512095 ]",
+  "[ 19/7 → 235/84 | s:hh pan:0.9233620996141421 ]",
+  "[ 20/7 → 247/84 | s:hh pan:0.890915741234015 ]",
+  "[ 3/1 → 37/12 | s:hh pan:0.8535533905932737 ]",
+  "[ 1238122213/393511398 → 847276553/262340932 | s:hh pan:0.8106731928589048 ]",
+  "[ 860605243/262340932 → 1323700481/393511398 | s:hh pan:0.7677528833339 ]",
+  "[ 2696991767/787022796 → 230214750/65585233 | s:hh pan:0.7175585019834292 ]",
+  "[ 2812167805/787022796 → 1438876519/393511398 | s:hh pan:0.6644931595798675 ]",
+  "[ 729434777/196755699 → 994441447/262340932 | s:hh pan:0.6139286689554151 ]",
+  "[ 1516457573/393511398 → 3098500379/787022796 | s:hh pan:0.557342689325327 ]",
+]
+`;
+
 exports[`runs examples > example "every" example index 0 1`] = `
 [
   "[ 0/1 → 1/4 | note:g3 ]",
@@ -6137,6 +6170,48 @@ exports[`runs examples > example "miditouch" example index 0 1`] = `
 ]
 `;
 
+exports[`runs examples > example "morph" example index 0 1`] = `
+[
+  "[ 0/1 → 1/8 | s:hh ]",
+  "[ 25/112 → 39/112 | s:hh ]",
+  "[ 27/56 → 17/28 | s:hh ]",
+  "[ 83/112 → 97/112 | s:hh ]",
+  "[ 1/1 → 9/8 | s:hh ]",
+  "[ 137/112 → 151/112 | s:hh ]",
+  "[ 83/56 → 45/28 | s:hh ]",
+  "[ 195/112 → 209/112 | s:hh ]",
+  "[ 2/1 → 17/8 | s:hh ]",
+  "[ 249/112 → 263/112 | s:hh ]",
+  "[ 139/56 → 73/28 | s:hh ]",
+  "[ 307/112 → 321/112 | s:hh ]",
+  "[ 3/1 → 25/8 | s:hh ]",
+  "[ 361/112 → 375/112 | s:hh ]",
+  "[ 195/56 → 101/28 | s:hh ]",
+  "[ 419/112 → 433/112 | s:hh ]",
+]
+`;
+
+exports[`runs examples > example "morph" example index 1 1`] = `
+[
+  "[ 0/1 → 1/8 | s:hh ]",
+  "[ 11/56 → 9/28 | s:hh ]",
+  "[ 13/28 → 33/56 | s:hh ]",
+  "[ 41/56 → 6/7 | s:hh ]",
+  "[ 1/1 → 9/8 | s:hh ]",
+  "[ 303934523/262340932 → 673454279/524681864 | s:hh ]",
+  "[ 188758485/131170466 → 820619173/524681864 | s:hh ]",
+  "[ 451099417/262340932 → 967784067/524681864 | s:hh ]",
+  "[ 2/1 → 17/8 | s:hh ]",
+  "[ 15/7 → 127/56 | s:hh ]",
+  "[ 17/7 → 143/56 | s:hh ]",
+  "[ 19/7 → 159/56 | s:hh ]",
+  "[ 3/1 → 25/8 | s:hh ]",
+  "[ 828616387/262340932 → 1722818007/524681864 | s:hh ]",
+  "[ 451099417/131170466 → 1869982901/524681864 | s:hh ]",
+  "[ 975781281/262340932 → 2017147795/524681864 | s:hh ]",
+]
+`;
+
 exports[`runs examples > example "mousex" example index 0 1`] = `
 [
   "[ 0/1 → 1/4 | note:C3 ]",