cmd = touch

target: target1 target2 target3
	sleep 1; $(cmd) target

target1: target1a
	sleep 1; touch target1;

target1a:
	sleep 1; touch target1a

target2: target2a
	sleep 1; touch target2

target2a:
	sleep 1; echo hi; touch target2a

target3:
	sleep 1; touch target3

clean:
	rm target* 2> /dev/null