A possible confounding between the orthogonal perceived spatial frequency shift and the vertical-horizontal illusion.
D000221:Adaptation, Ocular; D005556:Form Perception / Q000502:physiology*; D006801:Humans; D007088:Illusions / Q000502:physiology*; D009903:Optical Illusions / Q000502:physiology*; D010364:Pattern Recognition, Visual / Q000502:physiology*; D012399:Rotation