I thought this was kind of fun, it was interesting to see the different combinations the effects create. It was a bit challenging though too- keeping track of which effects were used where, and selecting the objects correctly.
The first one used a combination of Normal, difference, and difference.
Second one used a combinations of normal, color dodge, and difference.
Third one use a combination of normal, overlay, and difference.
I checked out the other posts, everyone had some great combinations and effects.