Abstract: An aid for learning roots includes a flat surface with a number of unit squares inscribed inside a larger square surrounded by a border. The board surface contains loops for mating engagement with rectangular patches having hooks for being detachably secured to the loops. There are 25 square patches of a number of colors, each corresponding substantially to a unit square and 25 rectangular strips each of width 1/5 a square side dimension. A perfect cube with unit squares inscribed on its face nests inside three intersecting orthogonal planar surfaces each having unit squares inscribed in a square of the same size as a cube face and a rectangular edge strip.

Abstract: A steadiness testing game has a convoluted conductive track along which a user moves a conductive ring, attempting to minimize contact of the ring with the track. Each instance of contact causes a signal such as a buzzer to be activated, and a counter may be provided to total the instances of contact to provide a score for the user. A timer may also be included, displaying the elapsed time taken by the user. In one embodiment the convoluted track is mounted so as to swivel to different angles to present different challenges to the user.

Abstract: A joint is formed by pushing a grooved tenon into a dovetail-shaped mortise containing a barbed wedge such that the wedge is forced into the tenon groove, thereby spreading the tenon to the dovetail shape of the mortise and anchoring the barbs into the tenon, thus securing the joint and preventing the tenon and mortise from separating.

Abstract: A joint is formed by pushing a grooved tenon into a dovetail-shaped mortise containing a barbed wedge such that the wedge is forced into the tenon groove, thereby spreading the tenon to the dovetail shape of the mortise and anchoring the barbs into the tenon, thus securing the joint and preventing the tenon and mortise from separating.