Figure 41: Vertical southeast declining dial, Church of St Thomas à Becket
Figure 42: Vertical southeast dial on the left and vertical northeast declining dial on the right
Figure 43: Vertical west declining dial, St Anne's church.
Vertical declining dials are attached to vertical walls that do not directly face North, South, East and West, but face some intermediate compass points. They can be be categorized into four types -
We name the declining wall from the direction which we face if we stand with our back to the wall looking straight ahead at right angles to the wall.
The gnomon is twisted out of the vertical in order for it to be parallel to the Earth's axis. It lies to the east of the 12-o'clock vertical line and thus among the afternoon lines if the dial declines toward southwest, but to the west among the morning hour lines with southeast decliners. The northerly dial differs from its southerly counterpart in the position of the gnomon and the order of the hour lines. The hour lines on the northerly dial are drawn in an anti-clockwise direction while the hour lines on the southerly dial are drawn in a clockwise direction.