Usage of comma(, ) with 'and'

Blue, red, yellow and green
or
Blue, red, yellow, and green

is there anyone could tell me which is correct?

Normally, the second example.

But look at this example:

The little cottages were painted blue, red, yellow and green, orange, and pink.

That could indicate some of the cottages were painted in two colours, i.e. yellow and green.

Hi Penny,

To add to what Molly has said, I have to admit I omit the comma before ‘and’ if the following word in the list is the last one. I base this on the assumption that ‘and’ is a substitute for the pause previously created by the comma(s).

Hope that makes sense!

Alan

But I’ve heard that one only needs a comma before “and” when one has more that two preceding words.

They were yellow, green and red.
They were yellow, green, red and purple.