Well, I was thinking that maybe it's something like, There has to be at least one "stick" letter. But then glass would've made it, but it didn't. Then I thought it was something like, It has to be made of all "stick" and/or all "round" letters, but then mint wouldn't have made it, but it did. NOW I'm thinking it's something like, That's a lie, I'm not tihnking anything.
Any hits?