diff --git a/src/main/kotlin/com/martianwabbit/hpglWriter.kt b/src/main/kotlin/com/martianwabbit/hpglWriter.kt
index d89576b..bf6b7d3 100644
--- a/src/main/kotlin/com/martianwabbit/hpglWriter.kt
+++ b/src/main/kotlin/com/martianwabbit/hpglWriter.kt
@@ -108,6 +108,5 @@ fun CompositionDrawer.velocitySelect(velocity: Double) {
 private fun StringBuilder.cmd(cmd: String) = this.appendln("$cmd;")
 private fun StringBuilder.cmd(cmd: String, i: Int) = this.appendln("$cmd${i};")
 private fun StringBuilder.cmd(cmd: String, i: Double) = this.appendln("$cmd${i};")
-private fun StringBuilder.cmd(cmd: String, vararg vectors: Vector2) {
-    this.appendln(vectors.joinToString(prefix = cmd, postfix = ";") { it.coords })
-}
+private fun StringBuilder.cmd(cmd: String, vararg vectors: Vector2) =
+    this.appendln(vectors.joinToString(separator = ",", prefix = cmd, postfix = ";") { it.coords })