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

2 × 2 brick, 1 side slit

Molded in yellow, lt blue, green and red.

2 × 2 brick, 2 side slits

Molded in yellow, lt blue, green and red

2 × 4 brick, 1 side slit

Molded in yellow, lt blue, green and red

2 × 4 brick, 2 side slits

Molded in yellow, lt blue, green and red