Celtic Knots

This is an entry for @sableRaph's weekly creative coding challenge. The theme for this week was "ancient," so I tried to make some Celctic knots, but eventually departed that look to something much less directly related to the topic.

The core of this sketch is an intersection algorithm between Bezier curves. At each intersection, one can alternate which curve goes over and which goes under. Then, when rendering the curves, one can leave a gap at "under" intersections to give the look of an overlap.