diff --git a/.shellcheckrc b/.shellcheckrc
new file mode 100644
index 0000000..8226afb
--- /dev/null
+++ b/.shellcheckrc
@@ -0,0 +1 @@
+external-sources=true
diff --git a/opt.sh b/opt.sh
index 133512c..7b7d70f 100644
--- a/opt.sh
+++ b/opt.sh
@@ -1,4 +1,6 @@
-source ./common.sh
+#!/bin/bash
+
+source "./common.sh"
 
 if [[ "${1}" == "" ]]; then
 	echo "Please provide a directory as the first argument"
diff --git a/stipple.sh b/stipple.sh
index 581bd45..9f4952e 100644
--- a/stipple.sh
+++ b/stipple.sh
@@ -16,6 +16,7 @@ fi
 INPUT=`realpath "${1}"`
 OUTPUT=`realpath "${2}"`
 INVERT="${3}"
+SINGLE="${4}"
 
 if [ ! -d "${INPUT}" ]; then
 	echo "Directory ${1} doesn't exist"
@@ -41,19 +42,16 @@ fi
 
 IMAGES=""
 
-#files in dir
-for png in "${INPUT}/"*.png ; do
+stipple () {
+	png="${1}"
 	filename=`basename "${png}"`
 	name=`echo "${filename}" | cut -d'.' -f1`
 	num=`echo "${name}" | awk -F'_' '{print $(NF)}'`
 	tmp=`mktemp`.png
+
 	bash white.sh "${png}" "${tmp}"
+
 	cd ~/src/stipple_gen/
-	if [ "${IMAGES}" == "" ]; then
-		part=`echo "${name}" | awk -F'_0' '{print $1}'`
-		IMAGES="${OUTPUT}/${part}_%06d_rendered.png"
-		VIDEO="${OUTPUT}/${part}.mov"
-	fi
 	bash stipple_gen.sh \
 		--display "false" \
 		--inputImage "${tmp}" \
@@ -84,8 +82,21 @@ for png in "${INPUT}/"*.png ; do
 		svgsort "${OUTPUT}/${name}.svg" "${opt}"
 		mv "${opt}" "${OUTPUT}/${name}.svg"
 	fi
+}
+
+i=0;
+#files in dir
+for png in "${INPUT}/"*.png ; do
+	stipple "${png}"
+	i=$((i+1))
 done
 
+if [[ "${IMAGES}" == "" ]]; then
+	part=`echo "${name}" | awk -F'_0' '{print $1}'`
+	IMAGES="${OUTPUT}/${part}_%06d_rendered.png"
+	VIDEO="${OUTPUT}/${part}.mov"
+fi
+
 ffmpeg -y -r ${FRAMERATE} -f image2 -i "${IMAGES}" \
 	-c:v prores_ks -profile:v 3 \
 	"${VIDEO}"