Tracking its movement in minute detail, researchers found that the snail's wingtips trace out a figure of eight to generate lift, just like of those of an insect.

研究者仔细追踪这种海螺的运动，发现它的翅膀末端能伸出数字8那样的形状来产力，就像其他昆虫那样。

Figures of eight till it's combined.

呈 8 字形切，直到粘到起。

Make sure you dig down to the bottom and you're cutting through in that figure of eight.

定要挖到最底下，呈 8 字形切开。

So you're going to use both hands and you're going to go down to your feet, and you're going to make a figure of eight. Okay. How are you doing?

所以你要用双手，然后向下到你的脚，做出个数字8的形状。好的。你做得怎么样？

Most birds flap their wings up and down, generating their lift force on the downstroke of the wing, but hummingbirds rotate their wings in a figure of eight motion.

大多数鸟类都会上下拍打翅膀，在翅膀向下运动时产升力，但蜂鸟却以 8 字形运动旋转翅膀。

So, take your pen and we're going to make a figure of eight with your pen.

所以，拿起你的笔，我们用笔画个数字8。