"How do they make those stone arches/bridges?" Without pics to be sure what you mean, I'm going to guess you've seen some objects made with lattices or terrains.

This is not my "second childhood". I'm not finished with the first one yet.

Time flies like an arrow; fruit flies like a banana.

"I'd like to die peacefully in my sleep like my grandfather....not screaming in terror like the passengers on his bus." - Jack Handy