LaTeX.org

I get symbols from here:

http://www.artofproblemsolving.com/Wiki ... eX:Symbols

Hi

I want to get a box displayed within the $ $ symbols. I find that I can get the triangles and circles with $\triangle$ but $\Box$ does not work. I cannot figure out why this may be so when the \Box is labelled along with the \triangle symbol in most user guides. I wonder what is causing this ...

I can get circle and triangle - but I am unable to get \Box, any ideas?

$\Box$ [$L_{\beta}$] $\triangle$ [$L_{\beta'}$] $\bigcirc$ [$L_{\alpha}$]