The development of single crystals with curved surfaces is an intriguing process, as flat facets and sharp edges are a well-established manifestation of the underlying crystallographic structure. To introduce curved crystal morphologies, the equilibrium of the facets' growth must be altered by chemical, mechanical, or other means. Crystals with multiple curved surfaces have been observed in biomineral structures, e.g., vertebrate bones and teeth, mollusk shells, as well as coral and coccolith skeletons of various organisms. These examples are based on calcium carbonate. Geogenic minerals have been shaped in laboratory by following the synthetic strategies used by organisms. Curved and hierarchical morphologies can be formed by a gradient of the building block(s) supersaturation, templating of amorphous phases and confined crystallization. Organic crystals having curved morphologies have been observed as well. For example, Yamamoto et al. showed recently that planar-chiral double-decker molecules assemble into vessel-shaped single crystals with curved concavity on quartz substrates. Choi and co-workers reported the formation of double and triple-decker flowers by crystallizing mixtures of C60 and C70 fullerenes. The crystallization of C70 is dominant at the early stage of the growth process due to its lower solubility, followed by co-crystallization of both C60 and C70 to form lateral petals. We reported morphologically very similar metal-organic frameworks (MOFs) demonstrating that such fascinating double-decker flowers structures can be formed from completely different materials without applying shaping directing additives. These finding indicates that the formation of such structures is an intrinsic and general structural property that most probably can be found in other classes of materials as well. Other examples of curved crystals include hybrids from protein and inorganic salts, edge-curved molecular crystals, and crystals grown into a curved confined geometry by means of vesicle membranes or liquid droplets. In recent years, our group has described the formation of a class of MOFs with varied and unusual morphological complexity. Curved lines, surface texture, re-entrant angles, and multidomain morphology have been shown to coexist with single crystallinity. Our MOFs also exhibit high complexity at the internal crystallographic structure level. They crystallize in a rarely observed space group, P622, characterized by a continuous metal-organic coordinative network and chiral channels. The starting materials are achiral. Interestingly, of the more than 1.28 million structures deposited in the Cambridge Structural Database (CSD), only 75 structures have the hexagonal space group P622 and of these, 56 are the MOFs of this series, from our group. In this work, we studied the processes leading to the appearance of curved lines. We followed the growth of the new crystals as they developed from hexagonal-like plates to complex doubledecker flowers with a total of 12 petals. The petal-like domains appear to grow from a central hexagon. The two tiers of the double-decker flower are aligned with respect to the crystallographic axes (a and b), that pass through the center of the petals; however, the two decks may differ greatly in terms of size. We followed the progression of the petals from their delineation by sharp planes to curved surfaces. The facets that comprise the petals at different stages of growth are indexed and their planes and solvent-exposed cross-sections are analyzed viz-a-viz the crystal structure. The development of the curved petals is related to the increased density of the progressionally exposed crystallographic planes.