Model was a small subtheme of the LEGO Basic theme, which began in the 1970s, was designed to be a more general, non-thematic series of sets. Unlike the themed sets that revolve around specific stories, characters, or concepts (e.g., space, city, or pirates), the Basic theme provided a collection of standard LEGO bricks and pieces, often in a variety of colors. The goal was to encourage free building and creativity without the confines of a specific theme or narrative.
1976 LEGO Sets
In 1976, town-focused play deepened with emergency and civic sets—police, fire, and services—while the train range saw continued refinement of 12V equipment and rolling stock. Basic Building Sets emphasized open-ended creativity. Fully fledged Space and Castle themes would follow in 1978.