remember that trick of using a couple mirrors to get an illusion of many? like if you needed way tons of soldiers  in rows and columns.. you'd use the mirrors to create an illusion of infinity rows and colums.

I remember someone doing something here and talking of it..but I can't find the post. (but found a huge amt of really old  fun posts to go thru..talk of optical illusions! )

Any idea how to do that mirror thing? And plz..no maths.. 2+2=5 to me.. 

cheers.. 
optically confused me.. 
rosie