transparency is a trap
 

Messages written in trans­parent ultra­vi­olet paint onto the glass windows of the glasshouse in the sculp­ture park of Orosko in Poland during the exhi­bi­tion Constructing Clouds (Oronsko) 2017.
Ultra­vi­olet paint is trans­parent and invis­ible for us, but visible for birds. It prevents them from colliding with the glass and dying.