Then, I just took three different sizes of square vases. You could use round vases...or square ones...or bowls...just pick three vessels that all have something in common. It could be different sizes and shapes of teapots or water pitchers.
I purchased two bouquets of cut flowers - one of green spider mums, the other of white calla lillies. I simply floated one large bloom in the 4" tall vases. Then, I let the bunch of calla lillies fall casually to the side of one of the tall vases. I arranged the rest of the mums without stems showing above the top of the vase, and voila! A fresh and casually elegant centerpiece for brunch (or whatever occasion you'd like).