based on the teaching at the beginning of this post i say this is over carved and too busy. it has no positive spaces. what i like about this carving is the use of shadows that make this design interesting. also the designs change to form patterns. at first glance i see several rosettes, then i see four diamonds. the more i look at it i see even more patterns. this change in shapes and patterns using shadows makes this carving interesting.
This is a very attractive, interesting coaster. The size of the chips are varied, but it looks as if a skew knife was used regularly on the sides of the cuts. This suggests to me positive space since it makes one side of the cut look more positive and one side look more negative. Interesting visual effects are created, and they draw my eye nicely into the carving.