Help/guidance needed: Seven colour laser spirograph with lens' Answered

So I'm trying to make a seven colored laser Spirograph, with lens' (that turn the beam into a crosshair for example) and I can't for the life of me work out how to make it work properly. I can design it so that I either have the lens or the Spirograph, but I cannot make it so that the Spirograph fits through the barrel of the lens thread. I think my best option might be to have two holes in the front of the device or use concave mirrors, what do you guys think?