you can have it sandblasted, if you do make sure it is on the outside
pane of glass if it is a insulated thermalpane. or else it will break
from the sun. if it is a single pane of glass do it on the inside for
easy cleaning. you could also acid etch the glass , its a paste you
paint on then wash off, and if both of those involve to much work, you
can have a glass shop cut you a new piece of obscure glass, there are
lots of diffent patterns. stick on stuff doesnt look all that great
and with condinsation it peels off or scratches.