v1=1\ +\ 1
v2=D
v3=C123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789
f() { v4="$*"; }

while [ ${#v2} -lt 1250 ]; do
	eval $v2=$((3+${#v2})) $v3=$((4-${#v2}))
	eval f $(($v2+ $v1 +$v3))
	if [ $v4 -ne 9 ]; then
		echo bad: $v4 -ne 9 at ${#v2}
	fi
	v2=x$v2
	v3=y$v3
done