The basic four-ball
juggling pattern. Each hand does
two in one hand, throwing from inside to out.
The balls do not move from hand to hand. Remember that, 'coz I'm not going to tell you again.
To learn the four ball fountain, make sure you can do columns in each hand. Keep practicing, because the final step is a big jump.
When you can do columns smoothly with your non-dominant hand, you are ready to add the last ball. Forget about columns. (Unless you want to do the four ball synch fountain.)
Start from a cold start, and just throw the balls to the same hand, alternating left-right-left-right-left-right. Even though the balls are not moving from one hand to another (Ok, so sue me... I did say it again), the pattern should have the same feel as a cascade. It's hard to explain why... just do it and find out for yourself.
That's all there is to it! Now pick up the balls and try again. And again. And again. And again...
Variations on the four ball fountain include the four ball synch fountain, where the two hands throw in time instead of alternately, pistons, where the hands throw side by side throws instead of inside to out, and the reverse fountain, where the hands throw outside to in.
Other four ball patterns are four ball tennis, five three, and the four ball Mill's Mess. But they are all way beyond even this Spud's incomparable skill... 8^)