conditional formating

Hi all

I know it is possible to program conditional formatting for a spreed sheet
but is there a way to make the cell a two color fill effect???? iv done it with an object like this

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but I cant seem to find anything for a cell.

the closest i got was the ordinary color

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what i need is colors that blend like one cell will be solid green say cell a1
cell b1 would be green to yellow cell c1 would be yellow to green and so on.

any help appriciated
ed