function r(word, bl)
    if word == "" then return true end
    local c = word:byte(1) | 32
    for i = 1, #bl do
        local b = bl[i]
        if c == b:byte(1) | 32 or c == b:byte(2) | 32 then
            bl[i] = bl[1]
            bl[1] = b
            if r(word:sub(2), bl:slice(2)) then return true end
            bl[1], bl[i] = bl[i], bl[1]
        end
    end
    return false
end

local function new_speller(blocks)
    local bl = blocks:split(" ")
    return |word| -> r(word, bl)
end

local sp = new_speller("BO XK DQ CP NA GT RE TG QD FS JW HU VI AN OB ER FS LY PC ZM")
local words = {"A", "BARK", "BOOK", "TREAT", "COMMON", "SQUAD", "CONFUSE"}
for words as word do
    print(string.format("%-7s %s", word, sp(word)))
end