Rose's Bowl

It was a real challenge to create an image that looks like an actual antique bowl.
  With a square opening at the top, a round base, and a flowery design,
it took the artist three months to complete the work. No photographs were used
– just mathematics. For example, the formula for the cross-sections of the bowl,
that includes the square top and the round base, is |x|^t +|y|^t = r^t where 1 ≤ t ≤ 2
and t = 1 at the top and t = 2 at the base.       Now for sale, in a limited edition.