动画脚本如下：

#!/bin/bash

set -eu
DIR="animate"
FILE="Federpendel"

NUM=0
rm -f ${DIR}/frame???.png
for ANG in $(seq 0 10 359) ; do
    echo "Creating frame $NUM ..."
    POS=$(echo "-3+0.8*c($ANG/45*a(1))" | bc -l)
    echo $POS $ANG
    sed -i "s/\\\def\\\myx{.\+}/\\\def\\\myx{$POS}/" ${FILE}.tex
    pdflatex -shell-escape ${FILE}.tex 1> /dev/null
    echo "Convert to png ..."
    NUMSTR=$(printf "%03d" $NUM)
    convert -density 256 ${FILE}.svg -shave 3 ${DIR}/frame${NUMSTR}.png
    NUM=$(($NUM+1))
done
cd $DIR
convert -delay 10 -loop 10000 frame*.png  Federpendel.gif
cd -

效果图：