How does the vine find the fence?

I am really enjoying the children's poems on the Korean Lab Web site. They are simple and innocent. Here is an example:

호박 덩굴 by 손길봉

호박 덩굴 끝에는
눈이 있지요.
울타리를 보고서
찾아가지요.

호박 덩굴 끝에는
손이 있지요.
울타리를 붙잡고
올라가지요.

Pumpkin Vine by Son Gil-bong

At the end of a pumpkin vine
there is an eye.
It sees the fence
and moves toward it.

At the end of a pumpkin vine
there is a hand.
It grabs the fence
and climbs up it.