The scientists studied how the angle of rock layers affects the crookedness of boreholes. They tested different angles and found that larger angles caused more drift in the borehole. Even at steep angles, the borehole still curved upwards. The twist in the borehole increased with steeper angles, reaching up to 112 degrees. Boreholes also shifted more horizontally at steeper angles, up to 28mm at 75 degrees. They also created an index to measure the crookedness, which was higher at shallower angles.