Monster animation

Explanation

Problem statement: You are at the center of a circular pond, and at the perimeter there is a monster who cannot swim. The monster can run 4 times faster than your swimming speed, and both of you can change direction instantaneously at will. You can run faster than the monster, so if you reach the edge at a point where the monster is not waiting to attack, you can escape. Describe a strategy for escaping the monster that works no matter how it chooses to move.

The strategy of always swimming directly away does not work: the result is illustrated in the above animation.