Overview
In toss juggling, columns, also known as One-up Two-up, is a juggling trick or pattern where the balls are thrown upwards without any sideways motion, distinguishing it from the fountain. The simplest version involves having three balls, with two going up simultaneously on either side, followed by one going up in the middle. One way to accomplish this is to juggle 2 balls in one hand and one ball in the other, so one hand has to move faster and further than in a regular pattern (cascade), whilst the other remains almost stationary. The hand juggling the center ball can alternate with each repeat to make the pattern symmetric.
Variations
The two-in-one is a variant using two balls in one hand (the hand with the "lone" ball is unused), "where the balls travel vertically in their own separate paths...Columns is really just a Two-in-One in one hand with a third ball thrown synchronously from the other hand."
There are many variations to the simple three-ball pattern. Some involve alternating the placement of the 'lone' inside throw, while others involve the two outside throws.
The 'lone' ball may be to either side of the two balls, and can have its position in relation to them altered whilst juggling the pattern by throwing it not at a vertical angle, or moving the hand holding it when it has been caught. This ball can also be thrown quickly from one hand to the other as in a box pattern, whilst the other two balls are in midair.
From Wikipedia (CC BY-SA 4.0).