Smooth min for organic shapes
min(a, b) combines two SDFs with a hard crease where they meet. The smooth minimum function smin() replaces that sharp join with a soft, organic blend — shapes melt into each other like liquid mercury or lava lamp blobs. The parameter k controls the blend radius: larger values create wider, gooier connections while smaller values keep shapes more distinct. This is the foundation of metaball effects and any shader art with an organic, blobby aesthetic.