A shooting star crashes on Earth, and a hideous blob emerges.
一颗流星撞上了地球，出现了一只可怕的粘液怪物。
It creeps and leaps, it glides and slides.
它会爬行、会跳跃；它会滑动、会滑行。
It's also unstoppable: weapons, fire, extreme temperatures
它也所向无敌：武器、火、极端温度，
no matter what you throw at it, it just regrows and continues its rampage.
不论你用什么方式攻击它，它总会再生并继续制造暴乱。
Its expansion is breathtaking; it doubles in size every hour.
它的扩展能力十分惊人；每小时，它的大小就会增大一倍。
But there's one opportunity: after each hour, it goes to sleep,
但有一个机会：每小时之后，它就会进入睡眠，
forming itself into a flat triangle and resting for a few minutes before it begins eating and growing again.
让它自己的形状变成扁平三角形，休息几分钟，接着又会开始吃东西成长。
Your only chance to save the planet involves a satellite-mounted nano-fission ray that can cut through the blob.
你只有一个机会能拯救地球，要用到装在卫星上的纳米分裂光束来将它切成两半。
When the blog is active it heals itself within seconds.
当怪物在活动时，只要几秒钟时间它就会愈合。
However, when you break the sleeping blob into two triangles, you make a critical discovery.
然而，当你把在睡觉中的怪物切成两个三角形时，你有了重大的发现。
The acute triangle portion, with all angles less than 90 degrees, is inert. It never "wakes up."
锐角三角形的部分，也就是所有角都小于90°的三角形，不再有生命力。它不再醒来。

The obtuse triangle, which has an angle greater than 90 degrees, wakes up as usual and keeps growing.
至于钝角三角形，也就是有一个角大于90°的三角形，还是一样会醒来并继续成长。
Similar experiments show that all shapes other than acute triangles, including right triangles, will also wake up.
类似的实验结果显示，除了锐角三角形之外的所有形状，包括直角三角形，都还是会醒来。
For the next few minutes, the blob is sleeping in its obtuse triangle form.
接下来的几分钟，怪物会以扁平三角形的形式进入睡眠。
You can make clean, straight-line cuts between any two points on or inside the triangle.
你可以针对三角形上或三角形内指定的任两个点做到精确的直线分割。
But you'll only have time to make 7 cuts while the satellite is above you.
但当卫星在你上方，可以进行切割的时间只够你切七次。
By the time it completes its orbit and returns,
当卫星完成绕行再回来时，
the blob will have consumed the entire world, if even a single portion that will wake up remains.
就已经来不及阻止怪物把整个世界吞噬了，即使只剩下怪物的一小部分也是如此。
How can you cut the blob entirely into acute triangles and stop it from destroying the planet?
你要如何把怪物切割成锐角三角形，阻止它摧毁地球？
While this seems doable at first, there's a hidden difficulty when it comes to avoiding obtuse and right angles.
虽然一开始会觉得这个方法可行，其实若想避免钝角和直角三角形，会碰到一个隐藏的困难处。
Every time you make a cut that reaches an edge, it either makes an acute and an obtuse angle, or two right angles.
每当你做的切割有接触到边缘，就会制造出一个锐角三角形和一个钝角三角形，不然就是两个直角三角形。
That makes it seems like you're doomed to keep creating obtuse angles.
看起来似乎你注定会一直制造出钝角三角形。
But as with so many of life's problems, we can look to pizza for inspiration.
但是，就像许多人生难题一样，我们都能从披萨上找到灵感。
Imagine squaring off the outside of a pizza, so that instead of a circle, it's an octagon.
想象一下，把披萨的外缘切平，披萨现在变成八角形，不再是个圆。
When we cut it into slices, each of the eight triangles is acute.
当我们把它切片，这8个三角形都是锐角三角形。
This works with larger polygons too.
对于边数更多的多边形，这招也一样可以。
Importantly, it also works for some polygons with fewer sides, including heptagons, hexagons, and pentagons.
重要的是，对于边数更少的多边形仍然可行，包括七角形，六角形，五角形。
That's good news, because if you cut off the sharp corners of the blob triangle,
这是个好消息，因为如果你把怪物三角形的尖角切除，
a pentagon is exactly what you'll be left with.
你就会得到一个五角形。
And just like a pizza, you can cut the blob pentagon into five acute triangles.
就像披萨一样，你可以把怪物五角形切成五个锐角三角形。
That's 7 cuts, and it renders the blob completely inert. You've saved the day!
一共要切七次，结果是怪物完全不再有生命。你拯救了世界！
Now you just need to figure out what to do with all of these giant, practically indestructible triangles.
现在，你只要想办法处理这些巨大且刀枪不入的三角形了。