As for color if you change where the colors go you will see a totally differant quilt block. If you want to get the same look I show here you need to use comparable colors in the same places I did.
If it is medium in mine make sure you use medium in the same place. If it is a light fabric use a light fabric. Make sure you use fabrics that will have contrast and don't blend together. You will lose the design if your mediums and lights are too much the same or your mediums and darks are too close in value.
Lay the two together and step back. Can you see each one apart from the other one? If not then you need to change your values. By that I mean your medium needs to be lighter than your dark or a color that is opposite of your dark.
You could use a blue for the dark and a red for the medium and a gold for the light. Just make sure your colors are in the right place too. Make sure when you make your Bostons that the medium is on the left if that is where it needs to be or on the right if that is where it is supposed to be for the quilt block you are making.
I like to use at least 3 colors usually but that can vary.