Wrote that a bit earlier

pong.txt

@@ -0,0 +1,14 @@
+·       
+ ·      
+  ·     
+   ·    
+    ·   
+     ·  
+      · 
+       ·
+      · 
+     ·  
+    ·   
+   ·    
+  ·     
+ ·      

wait.sh

@@ -0,0 +1,44 @@
+#!/bin/bash
+
+fail()
+{
+	printf "${@}\n" >&2
+	exit 1
+}
+
+FRAMES=()
+while [ -n "${1}" ]
+do
+	case "${1}" in
+		-p)
+			PERIOD="${2}"
+			shift 2;;
+		-f)
+			FILE="${2}"
+			IFS="\n"
+			while read LINE
+			do
+				FRAMES+=("${LINE}")
+			done < "${FILE}"
+			shift 2;;
+		*)
+			SEPARATOR="${1:0:1}"
+			INPUT="${1:1}${SEPARATOR}"
+			while [ -n "${INPUT}" ]
+			do
+				FRAMES+=("${INPUT%%${SEPARATOR}*}")
+				INPUT="${INPUT#*${SEPARATOR}}"
+			done
+			shift;;
+	esac
+done
+[ -n "${PERIOD}" ] || PERIOD=0.2
+[ -n "${FRAMES}" ] || fail "Syntax: ${0} [ -p PERIOD ] FRAMES"
+N=0
+
+while true
+do
+	printf "\r${FRAMES[$N]}"
+	N=$(((N + 1) % ${#FRAMES[@]}))
+	sleep $PERIOD
+done

wave.txt

@@ -0,0 +1,4 @@
+-_-¯-_-¯
+¯-_-¯-_-
+-¯-_-¯-_
+_-¯-_-¯-