Circular fringes can be produced from a gently defocused laser beam showing very nice spherical two-beam interference. Align the mirrors first without the collimator and lens, so that the beams from the two mirrors overlap on the beam splitter and screen. Then add the collimator and the lens. The photographs at the center and right above were taken with (center) and without (right) a neutral density filter.
Block either path and the fringes disappear. Room vibrations cause interesting fringe motion. A finger on the mount can move the pattern by a single fringe. A finger on the edge of one path shows heating of the air.