You know that old brain teaser about getting livestock across a river so a wolf doesn't eat them? You know, you can only carry so many of the critters at a time, but leaving a critter by itself guarantees death by wolf? I stumbled across a fun zombie-spin on this with different parameters care of Ted-Ed. You are an intern at a science lab on a mountain. Unfortunately, the scientist has created brain-hungry zombies. You and three other lab workers need to escape the zombies and cut off the exit bridge, but the bridge is old and so are some of the workers.

Watch this fun video and see if you can solve the puzzle. It took me a little bit, but I did get it before checking the answer.