The drawing is an enlarged generally front perspective view of the subject surface texture, at an angle looking downward on the front upper right hand corner of an exemplary envelope incorporating such surface texture. Stippling therein is intended to be representative of various alternating raised and lowered surface areas, and of curvatures there between, which form the repeating ribbed surface texture of the otherwise generally flatpack envelope container. The dotted lines are intended to generally represent envelope portions in cutaway, representing different sizes of various envelopes to which the subject surface texture may be applied.