441 is a three ball juggling Site Swap, also known as the Fake Box. It can be inserted as a single variation into a three ball cascade, or it can be run continually. This animation shows the "one off" version. To do this trick you need to be familiar with the Fountain Throw.

If you got this exactly right you can now go back to juggling the cascade without a break in your rhythm. Alternatively you can do another 441 immediately, the first 4 (the Fountain Throw) being done with the ball you just transferred.

Running this trick continually you end up with Fountain Throws on each side of the body and a transfer underneath, giving the same basic shape as The Box but at a much easier pace. Hence the name Fake Box.

Quotation from Tim Berners-Lee