While staring at my Apple Adjustable Keyboard, I discovered a new 3-D effect from the keys. The 2 parts of the keyboard must be slightly split with a gap between keys ("5" and "6") and ("T" and "Y") and ("G" and "H") and ("B" and "N").
When you stare at the keyboard to merge keys ("5" and "6") and ("T" and "Y") and ("G" and "H") and ("B" and "N"), 4 merged keys appear to be depressed! The depth of the depression depends on the size of the gap between the 2 parts of the keyboard.
If keys ("5" and "7") and ("T" and "U") and ("G" and "J") and ("B" and "M") are overlapped instead, 8 merged keys are seen to be depressed! Varying the size of the gap while staring at the keyboard creates an animation.
In effect, the horizontal gap is optically converted to vertical depression. The horizontal-to-vertical transformation is similar to the stereogram which produces a 2-level 3-D image from a repeated pattern of 2-D pictures, viewable without 3-D glasses. Unlike the stereogram, however, the new 3-D effect preserves both horizontal and vertical parallaxes since the objects (keys) are 3-D in the first place.
