A closed corner is when a shape or item isolates the corner of an image
When a symmetrical shape is cut off, by the border of the page or a larger shape, it will create an uncomfortable feeling.
When an item comes to close, or fuses with, the edge of the border.
When two items comes very close to each other,
or just barely fuse together.
An edge of an item is hidden by another
When multiple items, especially symmetrical ones, share the same axis
One item steals the edge or contour of another
When the placement of one item near another causes you to associate them too closely
Similar to a tension point or fused edge, but shares a whole edge
If you're looking to fix your tangents, you could: