A kangaroo kept getting out of his enclosure at the zoo.

Knowing that he could hop high, the zoo officials put up a ten metre fence.

But the next morning he got out again, and was found roaming around the zoo.

A twenty metre fence was put up. But again he got out.

When the fence was forty metres high, a camel in the next enclosure asked the kangaroo:

How high do you think theyll go?

The kangaroo said:

About a thousand metres, unless somebody starts locking the gate at night!