"The fountain pattern...can be stably performed in two ways...one can perform the fountain with different frequencies for the two hands, but that coordination is difficult because of the tendency of the limbs to synchronize.

"[5] The fountain is juggled in a circular fashion, distinguishing it from columns.

This circular motion is called 'outside circles' and is the fountain pattern shown in the animation.

This circle method can be reversed to create an 'inside circle' pattern whereby throws are from a position away from the body midline and catches are closer to the body midline.

In the columns method the balls all travel vertically up and down in their own 'column', and are caught from where they are thrown.