diff --git a/src/_includes/filters/header.js b/src/_includes/filters/header.js
index d0c5eb5..1dc780e 100644
--- a/src/_includes/filters/header.js
+++ b/src/_includes/filters/header.js
@@ -29,12 +29,12 @@ const polarToCartesian = (cx, cy, radius, alpha) =>
  * @param  alpha   number
  * @return hiccup
  */
-const arc = (cx, cy, radius, start, end) => {
+const arc = (_, { shape: { cx, cy, radius, start, end }, ...props }) => {
   const isLargeArc = end - start <= Math.PI
   const [ x1, y1 ] = polarToCartesian(cx, cy, radius, end)
   const [ x2, y2 ] = polarToCartesian(cx, cy, radius, start)
   const f = n => n.toFixed(2)
-  return ["path", {"d": `M ${f(x1)} ${f(y1)} A ${radius} ${radius} 0 ${isLargeArc ? '0' : '1'} 0 ${f(x2)} ${f(y2)}`}]
+  return ["path", {"d": `M ${f(x1)} ${f(y1)} A ${radius} ${radius} 0 ${isLargeArc ? '0' : '1'} 0 ${f(x2)} ${f(y2)}`, ...props}]
 }
 
 const numTiles = 10
@@ -57,9 +57,6 @@ const tenPrint = content => {
   const ys = range(numTiles + 1).map(y => width * (y / numTiles))
   const startAngle = random() < 0.5 ? quarterTau : 0
 
-  const template = arc(0, 0, radius, startAngle, startAngle + 3 * quarterTau)
-  template[1] = {...template[1], id: 'arc-a' }
-
   return ["svg.ten-print",
           {"viewBox": `${-radius} ${-radius} ${width + 2*radius} ${height + 2*radius}`,
            "xmlns": "http://www.w3.org/2000/svg",
@@ -67,7 +64,7 @@ const tenPrint = content => {
           ["style", ".arc { fill: none; stroke: none; }"], // avoid flash of unstyled content
           // pre-define our args
           ["defs",
-           template,
+           [arc, {"id": "arc-a", "shape": {"cx": 0, "cy": 0, "start": startAngle, "end": startAngle + 3 * quarterTau, radius}}],
            ["use", {"href": "#arc-a", "id": "arc-b", "transform": "rotate(90)"}]],
           // <use> the args with predefined rotations
           ["g", {"transform": "translate(0.5 0.5)"}, ys.map(y => xs.map(x =>