Automatic Binding Bricks

Automatic Binding Bricks
1949-1957
Cellulose acetate
Concave, solid studs
Square exterior and rounded interior corners
Slits on 1 or 2 sides
Hollow underside
No identifying markings
Specimen
Specimen
2x2 brick
2 × 2 brick, 1 side slit
Molded in yellow, lt blue, green and red.
2x2 brick
2 × 2 brick, 2 side slits
Molded in yellow, lt blue, green and red
2x4 brick
2 × 4 brick, 1 side slit
Molded in yellow, lt blue, green and red
2x4 brick
2 × 4 brick, 2 side slits
Molded in yellow, lt blue, green and red