Abstract: A mold box having a first mold plate and a second mold plate. The mold box includes a single elongate guide rail extending through a bore defined by the second mold plate. The single elongate guild rail allows the second mold plate to be movably arranged relative to the first mold plate.

Abstract: A modular toy construction system includes a first construction element with a first connector and a second construction element with a second connector. The first connector has at least two pairs of parallel connector surfaces, where one pair is angled relative to the other. The second connector includes a receiving part with a cross-sectional shape configured to pressure-fit with the first connector. The receiving part comprises carrier surfaces that align with the connector surfaces and includes a set of functional surfaces formed on elevated islands. Each functional surface faces a corresponding connector surface of the first connector. At least one of the functional surfaces is a pressure surface configured to locally deform the connector surface during coupling, providing secure engagement between the elements.

Abstract: A modular toy system comprising toy building elements including an arc toy building element. The arc toy building element has at least one knob receiving opening formed in a bottom surface or at least one knob formed in a top surface configured for coupling to complimentary coupling elements of another toy building element in a first direction. The arc toy building element also has an arc surface formed as a convex surface on the arc toy building element and extending over a length in a direction parallel to the top surface or to the bottom surface of the arc toy building element, the length is an integer multiple of a modular distance defining the spacing of a regular two-dimensional pattern for the toy building elements.