fast where the first and second sheets overlap as it does at the first roller tube cap end 22 to maintain a plane substantially parallel to the rotational axis for the leading edge of the first sheet 27 the orthogonal tracking spacer 13 begins to be wound under the first sheet outer edge 27 d at the start of the second revolution to compensate for the inner edge 47 c of the second sheet the width of the shade 10 can now be varied by extending or retracting the first cover tube 61 within and with respect to the second cover tube 62 as the first and second sheets 27 and 47 are extracted or pulled from the housing 60 a standard spring motor is used to exert a biasing force to retract the first and second sheets 27 and 47 into the housing 60 respectively mounted substantially perpendicular to the first and second sheets 27 and 47 proximate the first and second lower ends 27 b and 47 b are ribs 64 a and 64 b as shown in fig1 and 3 the first and second sheets 27 and 47 contact one another at the first and second lower ends 27 b and 47 b the ribs 64 a and 64 b are mounted to the sheets 27 and 47 so that each respective rib 64 a and 64 b projects outwardly and away from one another once the first and second sheets 27 and 47 have been withdrawn from the housing 60 so that the ribs 64 a and 64 b are a desired distance from the housing 60 the retaining hook 70 is utilized to secure the sheets 27 and 47 to.