http://guitarsphere.com/wp-content/uploads/2007/10/minor-pentatonic-scale.jpg


the question is, why is there different patterns to play the scale

Because the guitar is not laid out like a piano. It's the only instrument where the same note appears multiple times thus, you can play this one note multiple different ways, there by making multiple patterns to play.

^^vouch. The same notes in different spots allows you to play closer to where you want to go next. If you're playing a riff near the nut and jump into a solo, you might start your solo on the B at the 4th fret on the G string. BUT if your riff is near the 10th fret or something, you could jump into the same exact scale by playing the same B at the 14th fret of the A string.