These can easily be constructed out of old window frames and pieces of wood. (cbc.ca)
Covering almost every inch of the building with spray cans and stencil while some, like French artist Sambre, assembled old window frames and doors to create a surreal Alice in Wonderland - style area. (creativeboom.com)
Egg cartons and toilet paper rolls could be used as planters and old window frames made good cold frames. (treehugger.com)