One of my favourite patterns which involves nice flowing 'S' shaped carries while you juggle Two in one hand on each side alternately.
Start by juggling two in one hand in a rolling out pattern, which is the one where you throw the balls from the inside & catch on the outside & just hold the third ball idle in the other hand.
You begin a carry just as the hand doing the juggling starts to scoop to make the next throw. Carry the ball you are holding up & over in an arc from the outside to the inside over the top of your opposite arm. The next throw is a two in one hand throw as normal but it is made as an Under the arm throw underneath the carrying arm. Continue the carry underneath the ball in the air as it peaks, that is the top half of the 'S'. Throw the next ball as a cascade throw underneath the ball in the air & over the carrying hand. Scoop the carrying hand underneath the cascade throw to draw the lower half of the 'S' shape & make a rolling out two in one hand juggle. Carry on juggling a rolling out two in one hand pattern in the non-starting hand.
Practise the carry on both sides, start juggling two in one hand & change to juggling two in the other by putting in the 'S' shaped carry. You should've noticed that you draw an 'S' with the right hand & its mirror image with the left. Practise making nice smooth carries using your wrist as well as your arm. Bend your hand backwards & lead with the inside of your wrist, remembering to show as much of the ball to the audience as possible.
Keep practising the switch from side to side. Add in some rhythm by always switching after every four throws of a two in one hand juggle. Start counting from the first two in one hand throw of the carried ball & begin the next carry around the fourth throw. Count out to yourself, "One, two, three, carry, one, two, three, carry...". When you are comfortable reduce the number of throws all the way down until you are making only one two in one hand throw on each side & the cascade ball is continuously thrown back & forth from hand to hand.
After this the two hand weave can be easily extended into the Orinoco Flow.