all: t3 t4 t5
	echo all done

t3: t6 t7
	sleep 2
	touch $@

t7: t1
	sleep 2
	touch $@

t4: t8 t9
	sleep 2
	touch $@

t9: t2
	sleep 2
	touch $@

t1 t2:
	echo "run" >> /tmp/runlog
	touch t1
	touch t2

clean:
	$(RM) t* /tmp/runlog


t%:
	sleep 2
	touch $@