When increasing on both edges of a pieceoften used when shaping a waist or sleevesmirrored increases can add a touch of detail that really enhnace the symmetry of the piecesimilar to mirrored decreases of working ssk on one edge and k2tog on the other.
Make One right slanting: Insert the left-hand needle under the horizontal strand between the stitch just worked and the next stitch from the back to the front (photo 1), knit through the front loop (photo 2).
Make One left slanting: Insert the left-hand needle under the horizontal strand between the stitch just worked and the next stitch from the front to the back (photo 3), knit through the back loop (photo 4).