is bit_bin(bit_clr(255, 0, 8)), '0', "255, 0, 8 ok";
is bit_bin(bit_clr(255, 0, 2)), '11111100', "255, 0, 2 ok";
is bit_bin(bit_clr(255, 0, 3)), '11111000', "255, 0, 3 ok";
is bit_bin(bit_clr(255, 0, 4)), '11110000', "255, 0, 4 ok";

is bit_bin(bit_clr(255, 3, 1)), '11110111', "255, 3, 1 ok";
is bit_bin(bit_clr(255, 3, 2)), '11100111', "255, 3, 2 ok";
is bit_bin(bit_clr(255, 3, 3)), '11000111', "255, 3, 3 ok";
is bit_bin(bit_clr(255, 7, 1)), '1111111', "255, 7, 1 ok";