local palette = {
    [1] = 1, -- black wool
    [2] = 2, -- gray wool
    [3] = 3, -- light gray wool
    [4] = 4, -- quartz
    [5] = 5, -- stone
    [6] = 6, -- basalt
}

local pixels = {}

for y = 1, 64 do
    pixels[y] = {}
    for x = 1, 64 do
        pixels[y][x] = 0
    end
end

-- background
for y = 1, 64 do
    for x = 1, 64 do
        pixels[y][x] = 6
    end
end

-- head base (quartz)
for y = 18, 50 do
    for x = 18, 46 do
        pixels[y][x] = 4
    end
end

-- hair (black)
for y = 44, 50 do
    for x = 18, 46 do
        pixels[y][x] = 1
    end
end

-- temples / sides darker (gray)
for y = 26, 42 do
    pixels[y][18] = 2
    pixels[y][19] = 2
    pixels[y][45] = 2
    pixels[y][46] = 2
end

-- cheek shadows (gray / light gray)
for y = 24, 34 do
    for x = 20, 23 do
        pixels[y][x] = 2
    end
    for x = 41, 44 do
        pixels[y][x] = 2
    end
end

for y = 30, 38 do
    for x = 22, 25 do
        pixels[y][x] = 3
    end
    for x = 39, 42 do
        pixels[y][x] = 3
    end
end

-- jawline (stone)
for y = 18, 24 do
    for x = 22, 42 do
        pixels[y][x] = 5
    end
end

-- extra jaw shadow (gray) under cheeks
for y = 18, 22 do
    pixels[y][21] = 2
    pixels[y][43] = 2
end

-- chin highlight (quartz)
for y = 20, 22 do
    for x = 30, 34 do
        pixels[y][x] = 4
    end
end

-- eyes sockets (gray)
for y = 34, 36 do
    for x = 24, 28 do
        pixels[y][x] = 2
    end
    for x = 36, 40 do
        pixels[y][x] = 2
    end
end

-- eyes (black)
pixels[35][26] = 1
pixels[35][38] = 1

-- brow ridge (stone)
for x = 23, 41 do
    pixels[37][x] = 5
end

-- nose bridge (light gray)
for y = 30, 38 do
    pixels[y][32] = 3
end

-- nose sides (gray)
for y = 30, 36 do
    pixels[y][31] = 2
    pixels[y][33] = 2
end

-- nose tip highlight (quartz)
pixels[30][32] = 4
pixels[29][32] = 4

-- mouth shadow (gray)
for x = 27, 37 do
    pixels[26][x] = 2
end

-- lips (stone)
for x = 28, 36 do
    pixels[25][x] = 5
end

-- lower lip highlight (light gray)
for x = 30, 34 do
    pixels[24][x] = 3
end

-- jaw contour extra (black) for giga effect
for x = 22, 42 do
    pixels[18][x] = 1
end
pixels[19][21] = 1
pixels[19][43] = 1
pixels[20][20] = 1
pixels[20][44] = 1

local function selectBlock(code)
    local slot = palette[code]
    if not slot then return false end
    if turtle.getItemCount(slot) == 0 then return false end
    turtle.select(slot)
    return true
end

local function placePixel(code)
    if code == 0 then return end
    if selectBlock(code) then
        if not turtle.place() then
            turtle.dig()
            turtle.place()
        end
    end
end

local function build()
    for y = 1, 64 do
        local reverse = (y % 2 == 0)
        if not reverse then
            for x = 1, 64 do
                placePixel(pixels[y][x])
                if x < 64 then turtle.forward() end
            end
        else
            for x = 64, 1, -1 do
                placePixel(pixels[y][x])
                if x > 1 then turtle.forward() end
            end
        end
        if y < 64 then
            turtle.up()
            turtle.turnLeft()
            turtle.turnLeft()
        end
    end
end

build()