Wow I missed the hand-stand, maybe she had an itchy head - you know sometimes you get an itch and you just cant' reach it
That probably sounds silly I know but would there be reason she'd do that or is she just stretching? I must confess ignorance about the incubation phase, when our pair had their eggs here the web cam was at a distance so I never got to see the eggs close up like this.
Also when you refer to the piping, do you mean like a kind of line across the egg? Cause I did see kind of a squigly line on one of them this morning or I thought I did but then I thought nah..must just be the reflection of the sun.