Fake Vector3

local Vector3 = {
    new = function(n1,n2,n3)
        local p = {}
        p.x, p.y, p.z = n1,n2,n3
        setmetatable(p, {
            __tostring = function()
                return p.x..","..p.y..","..p.z
            end;
            __index = function(self,func, val, val2, val3)
                if func == "SetX" then
                    return self.new(val,self.y,self.z)
                elseif func == "new" then
                    print(val1, val2, val3)
                end
            end
            }
        )
    return p
    end;
}

local firstv3 = Vector3.new(1,2,4)
print( firstv3:SetX(20) )