diff --git a/packages/core/drawLine.mjs b/packages/core/drawLine.mjs
index 73fac46b..05c857de 100644
--- a/packages/core/drawLine.mjs
+++ b/packages/core/drawLine.mjs
@@ -1,12 +1,15 @@
 import { gcd } from './fraction.mjs';
 
-function drawLine(pat) {
+// TODO: make it work for stacked patterns + support silence
+
+function drawLine(pat, chars = 60) {
   let s = '';
   let c = 0;
-  while (s.length < 60) {
+  while (s.length < chars) {
     const haps = pat.queryArc(c, c + 1);
     const durations = haps.map((hap) => hap.duration);
     const totalSlots = gcd(...durations).inverse();
+    s += '|';
     haps.forEach((hap) => {
       const duration = hap.whole.end.sub(hap.whole.begin);
       const slots = totalSlots.mul(duration);
@@ -15,7 +18,6 @@ function drawLine(pat) {
         .map((_, i) => (!i ? hap.value : '-'))
         .join('');
     });
-    s += '|';
     ++c;
   }
   return s;
diff --git a/packages/core/test/drawLine.test.mjs b/packages/core/test/drawLine.test.mjs
new file mode 100644
index 00000000..d697c793
--- /dev/null
+++ b/packages/core/test/drawLine.test.mjs
@@ -0,0 +1,11 @@
+import { fastcat } from '../pattern.mjs';
+import { strict as assert } from 'assert';
+import drawLine from '../drawLine.mjs';
+
+describe('drawLine', () => {
+  it('should work', () => {
+    assert.equal(drawLine(fastcat(0, [1, 2]), 10), '|0-12|0-12');
+    assert.equal(drawLine(fastcat(0, [1, 2, 3]), 10), '|0--123|0--123');
+    assert.equal(drawLine(fastcat(0, 1, [2, 3]), 10), '|0-1-23|0-1-23');
+  });
+});