Photogram

Place objects (leaves, twigs, tools, hand, etc.) directly on the photo paper, under the enlarger.
Try a 5 second exposure at F8.
Add, move or change the objects, add more exposure.
Add a negative in the carrier for different effects.
Bill Westheimer Photograms

http://www.photogram.org/frame.html

Man Ray the granddaddy of the photogram
Picasso did it too