Abstract: A molding apparatus to provide composite plastic articles within the mold is provided. The apparatus includes upper and lower sections which when in a closed position, form a mold cavity divided into two separated chambers by partitions in the upper section. Elements of a desired configuration are formed in the chambers by injecting molten plastic therein and cooling. After formation of the elements, the upper section of the mold is removed and with it, the partitions separating the cavity into chambers. The elements, which are now at opposite ends of an unblocked cavity, are then driven into engagement with each other by a driving means while still in the mold. The joined elements are then ejected from the mold as a composite article. In the preferred embodiment, the elements are interlocked "E" shaped devices which form a solid cube when joined.