A modular basin apparatus includes a first panel, a second panel and a third panel. The panels include a plurality of slots that receive portions of the other panels. A user may assemble the panels to form a three-dimensional basin apparatus. A concave cavity is formed on the upper side of the apparatus when assembled, and the cavity may be receive materials depending on the application of the assembly. In some embodiments, the apparatus may be used as a modular fire pit, chair, table, or other device. A fourth panel may rest against the first, second and third panels to provide an upper surface. In some embodiments, all panels include the same planform profile and outer dimensions such that they may be stacked in an arrangement having a uniform outer profile for improved transport and storage.