What I would like to have is:
IF A1 in Sheet 2 is blue
Then A1 in Sheet 1 changes to blue
I know I can get the color of A1 in Sheet 2 b
The GET.CELL function, whilst useful, comes from the old XLM macro language which was used before VBA. You may encounter restrictions using this e.g. at that time Excel used a limited number of colours (I have read somewhere around 60?).
Alternatively, with a bit of VBA, you could experiment with the Interior Object and also the Font Object :
Sheets("Sheet1").Range("A1").Interior.Color = vbBlue
Sheets("Sheet1").Range("A1").Font.Color = vbYellow
If Sheets("Sheet1").Range("A1").Interior.Color = vbBlue Then _
Sheets("Sheet2").Range("A1").Interior.Color = vbBlue
If Sheets("Sheet1").Range("A1").Font.Color = vbYellow Then _
Sheets("Sheet2").Range("A1").Font.Color = vbYellow
You will likely need to explore the various ways of specifying the colors to use to give you maximum control/flexibility.