How to do square sides?

[Flojobunny]

Hi, I'm new to doing the 6" squares and I've seen a pattern I like that's like a square round a square, 2 different colours.
When doing the sides of the outer side what happens to the wool when you change colour for the inside square?
Presumably you can't have it hanging across the back or have 2 balls of the same colour for each side?
Hope this makes sense.

Can you find a picture?

I think so. Assuming it's a square in colour A inside a square of colour B, you would have two balls of B.

First however many rows are in B only. Then on a suitable row (say about 10) you knit 10 stitches of B (say) and then 20 of A, then another 10 of B. So you need a second ball of B to do those 10 stitches on the 'far' side of the row.

Have a look at for some guidance.

Btw you don't need an entire new ball for the second ball of B, you just unwind a few feet from ball B and wind it up into a mini-ball.

Thanks that makes sense