Lua螺旋矩阵：顺时针绕圈的边界收缩

local function spiral(n)
    local m = {}
    for i = 1, n do m[i] = {} end
    local top, bottom, left, right = 1, n, 1, n
    local v = 1
    while v <= n * n do
        for c = left, right do m[top][c] = v; v = v + 1 end
        top = top + 1
        for r = top, bottom do m[r][right] = v; v = v + 1 end
        right = right - 1
        for c = right, left, -1 do
            m[bottom][c] = v; v = v + 1
        end
        bottom = bottom - 1
        for r = bottom, top, -1 do
            m[r][left] = v; v = v + 1
        end
        left = left + 1
    end
    return m
end

local p = getplayerbyname("grid01")
local m = spiral(5)
sendmsg(p, 1, table.concat(m[1], ","))
sendmsg(p, 1, table.concat(m[3], ","))