Upholstery comprising: first and second stitchable materials, a plurality of first alignment features (30T,30E,30B) provided in a joining region on the first stitchable material, each of the plurality of first alignment features being a marking on the first stitchable material, a plurality of second alignment features provided in a joining region on the second stitchable material, and a plurality of sequentially formed stitches cooperating to couple the first and second stitchable materials to one another to establish a flat seam on the first and second stitchable materials, wherein the pluralities of first (30T, 30E, 30B) and second alignment features are mated such that each of the first alignment features (30T, 30E, 30B) provided on the first stitchable material is positioned to be aligned with a companion one of the second alignment features provided on the second stitchable material, thereby enabling alignment of the first and second stitchable materials in a manner to establish an alignment mechanism for alignment of the first and second stitchable materials that further enables formation of the flat seam which comprises a plurality of sequentially formed stitches, wherein each of the plurality of first alignment features comprises indicator means for providing the marking on the first stitchable material that is visible to a sewing person using the alignment features during a sewing process and during alignment of the first stitchable material relative to the second stitchable material and formation of the flat seam on the first and second stitchable materials and is invisible to a person viewing the top surface (21 T, 22T) of the first and second stitchable materials after formation of the flat seam, wherein the indicator means is a line, a symbol or a series of symbols. first and second stitchable materials, a plurality of first alignment features (30T,30E,30B) provided in a joining region on the first stitchable material, each of the plurality of first alignment features being a marking on the first stitchable material, a plurality of second alignment features provided in a joining region on the second stitchable material, and a plurality of sequentially formed stitches cooperating to couple the first and second stitchable materials to one another to establish a flat seam on the first and second stitchable materials, wherein the pluralities of first (30T, 30E, 30B) and second alignment features are mated such that each of the first alignment features (30T, 30E, 30B) provided on the first stitchable material is positioned to be aligned with a companion one of the second alignment features provided on the second stitchable material, thereby enabling alignment of the first and second stitchable materials in a manner to establish an alignment mechanism for alignment of the first and second stitchable materials that further enables formation of the flat seam which comprises a plurality of sequentially formed stitches, wherein each of the plurality of first alignment features comprises indicator means for providing the marking on the first stitchable material that is visible to a sewing person using the alignment features during a sewing process and during alignment of the first stitchable material relative to the second stitchable material and formation of the flat seam on the first and second stitchable materials and is invisible to a person viewing the top surface (21 T, 22T) of the first and second stitchable materials after formation of the flat seam, wherein the indicator means is a line, a symbol or a series of symbols.