The 777X program is hardly zipping along.  The four test aircraft have been in use for a while now but the certification is not due until the end of 2023.  After being built at Everett, the test jets all headed to Boeing Field.  However, the fourth test aircraft, WH004, recently went back to Everett.  I’m not sure why but it did a bit of flying out of there.  One evening, I popped up to get a photo or two when it was returning.  Conditions were ideal but a white jet will always have a bit of light on the airframe.