up-and-down (?.)

• alternate
• back-and-forth
• orthodiagonal
• orthogonal
• perpendicular
• plumb
• plunging
• precipitous
• reciprocal
• reciprocative
• right-angle
• right-angled
• right-angular
• seesaw
• sheer
• sine wave
• steep
• straight-up
• straight-up-and-down
• to-and-fro