DIY wooden puzzle Random Generator is a device that generates random numbers and provides different random results based on probability theory. How it does this is exactly what the Ugears STEM model will demonstrate. The main element of the 3D puzzle Random Generator’s design is a cube with an octahedron inside it that in its turn contains a metal ball to provide weight. This construction is powered by a rack-and-gear drive initiated manually and providing energy through a driven gear that rotates a three-axle gear. This is how the cube with all its contents begins to move, which is important for summoning the magic of randomness. Of course, we can only call it magic until we know the science of it. And to learn it, let us take a closer look at the main structure. The vertices of the octahedron coincide with the sides of the cube. In this way as the energy of the system expires and it stops moving, gravity suspends the metal ball in the lowest part of the octahedron and due to the inclination of the walls it rolls within, it ends up in one of the octahedron’s vertices pulling in down. The probability to get any of the vertices facing down is virtually the same due to symmetry of the octahedron that rotates freely around the axis of its mass. This leads us to a simple conclusion that the probability to receive one of six answers is 1/6 or 0.167. Every side of the cube positioned by the vertex of the octahedron, has a message: one says “YES”, the other “TRY AGAIN”, etc. Random Generator, educational mechanical model kit Model size: 6.81*4.8*5.2 in (17.3*12.2*13.2 cm) Package size: 8.07*7.4*2.48 in (20.5*18.8*6.3 cm) Number of components: 160 Estimated time of assembly: 4 hours