Squircle Pen Cup

This is just like a regular pen cup, but instead of having a circular or rounded square cross section, this uses a super-ellipse shape (otherwise known as a “squircle”) to avoid the abrupt, distracting transition between a fillet and its two straight edges. I created this to celebrate the new addition of the corner-shape: squircle property introduced in the CSS Borders and Box Decorations Module Level 4. Happy printing!