The Wikipedia article section OneWeb satellite constellation; Design characteristics tells us:
The satellites will operate in the Ku band, communicating in the microwave range of frequencies in the 12–18 GHz portion of the electromagnetic spectrum. The satellites use a technique called "progressive pitch" in which the satellites are slightly turned to avoid interference with Ku-band satellites in geostationary orbit. The user terminal antenna on the ground will be a phased array antenna measuring approximately 36 by 16 centimeters (14.2 by 6.3 in) and will provide Internet access at 50 megabits/second downlink bandwidth (almost certainly less uplink, but this number remains hard to pin down).
Question: What is OneWeb's constellation's "progressive pitch" and how does it avoid interference with Ku-band satellites in GEO. Earth is large and each OneWeb satellite's footprint is substantial (as is each GEO satellite), so how does this prevent interference over all necessary area at the same time?