mounting brackets 30 as shown in fig1 when the desired arrangement of panel assemblies 25 is achieved a reveal strip 55 of a predetermined length is installed in the reveal cavity as at 60 between adjoining panel assemblies as illustrated in the composite reveal strip insertion sequence shown in fig1 to complete the installation initially the beveled edge 55 a of the reveal strip 55 is inserted into the reveal cavity 60 in generally perpendicular relation to the acm panels 15 into contact with spring clips 40 45 as shown by directional arrows 65 it will be understood that the function of the spring clips 40 45 is initially to guide the reveal strip 55 into its installed position in the reveal cavity 60 and then to lock the reveal strip into such position still referring to fig1 this is accomplished by pushing the reveal strip 55 inwardly against the spring bias of curved spring clips 40 to deform such clips 40 to a compressed condition shown by broken line 43 in fig1 b next the reveal strip 55 is partially rotated shown by directional arrows 65 in fig1 about its longitudinal axis into contact with angular spring clips 45 to deform such clips 45 to a compressed condition.