Confusing directions in my afghan

I am knitting a block afghan with circular kneedles. It changes colors but it states in the directions “to avoid holes when changing colors, always bring new color up over old” What does that mean???


When you add a colour for a new block, you will leave the old colour attached. Each colour block will have its own ball of yarn. When you arrive back at a colour change that has a ball of yarn attached already, you have to bring the new colour up over the old colour before knitting on. This twists the two colours together. Otherwise, if you just dropped the old colour and picked up the new colour, the blocks wouldn’t be joined together.

This technique is called intarsia and you can find a video demonstrating it, including colour changes, on this page, about half way down under the heading ‘How to knit with 2 colors at a time’