Toy-building elements including various combinations of the following features: a top having a broad surface and at least one projection or ball-shaped coupler extending above the broad surface; an interior having contact surfaces that are accessible through an open bottom and are adapted for effecting a releasable restraining engagement with an interconnectable projection or ball-shaped coupler on a second toy-building element; at least one sidewall including at least one groove for effecting a releasable restraining engagement with a tongue in a sidewall of another toy-building element; at least one sidewall including at least one tongue for effecting a releasable restraining engagement within a groove in a sidewall of still another toy-building element; and at least one sidewall including an axel-shaped or ball-shaped coupler for effecting a variably positional engagement with an interconnectable coupler in yet another toy-building element. These toy-building elements are combined with others to assemble person-like and vehicle-like toy figures.