There are two different ways to soften the corners of a square: the first and easiest is to just radius the corners. Take a square block of wood, round off the corners, done. This is the most common route. The second is to use a spline to create a gentle curve that flows from side to side. This is what we do for our products.
Originally, a spline was a physical tool (a thin piece of wood or other pliable material) used to help draw a gentle bending curve between fixed points. Now, we use computer software to model spline curves as we design our products, and then produce the shape out of solid hardwood. This method allows us to create a continuous curve around the edge of the square, rather than an abrupt change from flat to rounded.