Selecting a small picture will enlarge it. The segment of self-intersection is visible. The pinch point is visible from above. Part of the self-intersection is visible.
Color is assigned according to v parameter.
This is the same view depicted in the first picture. The coloring helps to illustrate that the rectangle is intersecting itself, not being creased in the middle. This is the same view depicted in the second picture. Whitney's Umbrella seen from underneath.