Batima bricks

I just found an old cookie tin box filled with these roundabout 100 years old charming bricks in great condition. For me the black, gray and light gray bricks are new colors. Any info on these 3 colors would be much appriciated - as far as I know, they didn`t appear in the Batima wooden boxes.

Batima is the earliest known plastic construction toy, made in Belgium circa 1930, compression moulded from casein formaldehyde (milk curds hardened with formaldehyde).

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