I own a damaged Tessar 3,5/40mm from a Rollei 35. The focus ring is missing, but it can be focused by turning the front ring. The aperture is in function but can only be set by a tiny rod at the lens´ tube.
Glueing a bent nail into this rod let me set the aperture easier.
I used the bayonet of a Holga-for-m4/3-lens to mount the Tessar to my Lumix G1. Glue, tape and some plastic lens caps were used to give it some housing. A little plastic piece with three dents holds the nail and sets the aperture; only 3,5 - 8 - 22 are possible.
Some examples @ f8:
Some bokeh @ f3,5: