toGray: function [n]-> xor n shr n 1
fromGray: function [n][
    p: n
    while [n > 0][
        n: shr n 1
        p: xor p n
    ]
    return p
]

loop 0..31 'num [
    encoded: toGray num
    decoded: fromGray encoded

    print [
        pad to :string num 2 ":"
        pad to :string .format:".b" num 5 "=>"
        pad to :string .format:".b" encoded 5 "=>"
        pad to :string .format:".b" decoded 5 ":"
        pad to :string decoded 2
    ]
]