the case for the square corner
Every corner in werkstatt is ninety degrees. It is the one decision that makes everything else look like one thing.
Rounded corners are the default of our decade. Most interface kits ship with an eight-pixel radius, most buttons are pills, and most people stopped noticing. The roundness promises friendliness, and it mostly delivers. It also costs something that is easy to miss until it is gone.
a fourth shape
A rounded rectangle is not a square and not a circle. It is a fourth shape, and once it is in the system every element has to decide how much of one it is. Four pixels? Eight? Twelve? A pill? Each answer is a small personality, and a product full of small personalities has none.
Then the nesting problem arrives. A rounded box inside a rounded box needs a smaller radius, exactly the outer radius minus the padding, or the two curves fight. Designers know the formula and almost nobody applies it, so most interfaces have corners that are slightly, invisibly wrong everywhere.
The square corner has no parameter. Zero is zero. A card inside a card inside a panel lines up without arithmetic, and a border is a line, not a curve that has to be matched.
curves the school allowed
The Bauhaus was not afraid of curves. Breuer's chairs are bent tube; the lamp Wagenfeld and Jucker made in 1924 is a sphere on a cylinder on a disc; Brandt's teapot is half a ball. But every one of those curves is a real circle, a whole radius you could draw with a compass. None of them is a corner softened by a few degrees. The curve is a shape doing a job, not a mood applied to a shape.
That is the rule we keep. A circle is allowed wherever a circle is wanted: the avatar is a full circle, not a rounded square; the toggle's dot is round because it travels; the play icon sits on a disc. Everything that is a box is a box.
what replaces the softness
Rounding does three jobs in most products, and each has a flat replacement. It signals that a thing is pressable: we use a verb, a box and a 48-pixel height. It separates a surface from its background: we use a 3-pixel rule. It softens density: we use the 8-point scale, so there is always air between boxes.
The hover state is a color, not a glow. Selection is yellow. Depth is overlap. None of these needs a curve, and all of them work in black and white, which rounding does not.
where it is hard
- Pills are the convention for tags. Ours are boxes, and people learn it in about a second.
- A square toggle looks unusual. It is a square track with a round dot, two shapes doing two jobs, and it reads as a switch because the dot moves.
- Square corners can look abrupt at small sizes. Size and spacing are the cure, never a radius.
The system makes no exception in the interface and none in print. Where a corner meets another corner, they meet at ninety degrees, and the whole product looks like it was made by one hand.