Nine-Boxes, aka: https://developer.mozilla.org/en-US/docs/Web/CSS/Reference/Properties/border-image-slice https://developer.mozilla.org/en-US/docs/Web/CSS/Refer

Nine-Boxes, aka: https://developer.mozilla.org/en-US/docs/Web/CSS/Reference/Properties/border-image-slice https://developer.mozilla.org/en-US/docs/Web/CSS/Reference/P... ...and that was a grand improvement over having to make a "tic-tac-toe" table where you'd be putting things in the particular surrounding cells to fake these fancy border-types.