Well, they're supposed to differ a little at least, since the table is round with a flat top while the parasol is round with a curved top. The side-view on the table is also clear, where the shading is softer on the parasol. Since RTP itself has an inconsistent top-down perspective on things (compare a tree to the table, for instance), it's really hard to peg the exact perspective. The other parasol was more obviously off since it had the same shape as the table, but different angle.