The Threaded Box is a variation
of the Box in which each vertical throw is caught under-the-arm, with that
top arm weaving through the pattern. This creates a much more fluid juggling
trick than the normal Box, while also increasing the difficulty by rasing
the likelihood of collision. The Threaded Box is generally juggled at a
greater height than the regular Box, therefore is is also a fair amount
To learn the Threaded Box, start with one ball in each hand. Bring your non-dominant hand over to the dominant side of your body while also shifting your dominant hand farther from the center of your body (so your arms aren't crossed). Raise your dominant hand up about six inches, and then make a vertical throw from your non-dominant hand. Simultaneously, make a horizontal pass from your dominant hand to your non-dominant hand. The pass should be timed such that it goes under the vertical ball. As your non-dominant hand catches the pass, you are going to pull it back to the non-dominant side of your body, at a distance away from the center that matches the distance from the center that your dominant hand was before the pass. Your dominant hand should then be crossed over to the non-dominant side of your body (essentially your hands are mirroring the position they were in at the start). As the vertical ball first thrown begins to descend, make a horizontal pass from your non-dominant hand while simultaneously bringing your dominant hand up to receive it near the center of your body. Your non-dominant hand will then cross underneath your dominant hand to catch the vertical ball.
As shown, practice this on both sides. To add in the third ball, you are going to start with two balls in your dominant hand and one ball in your non-dominant. Bring your dominant hand over to your non-dominant side and make a vertical throw. Then, bring your dominant hand back over to your dominant side while also bringing your non-dominant hand to your dominant side (your hands should now be in the same position as they would be at the beginning of step one). As the first ball begins to descend, make a second vertical throw, from your non-dominant hand this time, and then make a horizontal pass from your dominant hand to your non-dominant hand (just like you did in step one). Right after you make the pass, cross your dominant hand underneath your non-dominant hand and catch the first ball. As you non-dominant hand catches the pass, bring the hand to the outside of your body. Catch the second ball with your non-dominant hand.
Once again, practice this on both sides as shown in the animation above. To run the full Threaded Box, simply make another vertical throw/horizontal pass combination as the second vertical ball begins to descend. This will mark the beginning of a second cycle, after which you will simply keep repeating cycles on alternating sides.