Abstract: A constructional toy comprising a plurality of elements which can be assembled together to form a variety of three dimensional structures. The elements include a triangular prism shaped brick element comprising a plurality of walls. The walls define a male mating side having a male engagement feature which extends from the brick. The walls also define a female mating side which defines a cavity configured for receiving an engagement feature of the same configuration as provided on the male mating side.

Abstract: A toy building block set includes multiple polyhedron blocks of different lengths removably attachable together. Each block includes at least a top and four side walls. At least one connector extends from the top and includes opposing interior and exterior surfaces. A recessed area is provided at the bottom of each block. Engagement projections or depressions are provided on the connector and the remaining engagement structure are provided in the recessed area of each block where they might fully or partially engage or not engage with structures on the connector. The mechanical interference engagements and resulting engagement forces provided between any two of the blocks are less than three and even less than two times the number of engagements and resulting engagement forces provided by a mated pair of the smallest polyhedron blocks of the set.