Toy building block

A toy building block comprising a body having parallel top and bottom faces and first and second substantially planar lateral faces orthogonal to the top and bottom faces, a lateral male feature projecting from the first lateral face and a lateral female feature recessed into the second lateral face, the lateral male and female features matingly engageable with female and male lateral features of other of said blocks to achieve interlocking connection of the block with said similar blocks, the block further characterized in that:

• a top male feature projects from the top face and a bottom female feature is disposed on the bottom face, the bottom female feature being matingly engageable with top male features of other of said blocks, and the lateral male and female features have respective first and second interlocking means configured to engage with one another in a first mating position and in an alternative second mating position, the first mating position establishing a first connection between the blocks wherein the lateral male feature is inserted substantially fully into the lateral female feature such that adjacent faces of the connected blocks are parallel and proximate one another to inhibit swivelling movement of the connected blocks relative to one another in a plane orthogonal to the top and bottom faces, and the second mating position establishing a second connection between the blocks wherein the lateral male feature is inserted less than fully into the lateral female feature such that the adjacent faces of the connected blocks are separated from one another by a distance sufficient to permit said swivelling movement.