Abstract: A slope block assembly having a bubble level with an eccentrically mounted slope block detachably carried on one end of the level. The slope block has an offset turning axis with a plurality of supporting surfaces, all located at different distances from the turning axis. The support surfaces cooperate with an undersurface or support point on the level to direct a laser beam at a desired angle with respect to a round or flat reference surface. Grooves are provided on the slope block support surfaces as well as on the level undersurface to support the level and slope block assembly on a round or curved reference surface.