Notice that the color coordinates are opposite (or across the wheel) from one another. For example, view the green slice that lists A major and its minor relative f #. Opposite (across the wheel) is a green slice that lists A flat major and f minor. The Keys opposite or across The Music Wheel are half-step tones from one another. 

The orange slice containing E major and c#minor are opposite (or across) from E flat major and C minor, also an orange slice. These opposite Keys are half-step tones from one another.

The lavender slice containing B major and g# minor are across from B flat major and g minor, also a lavender slice.These opposite KEYS are half-step tones from one another on a keyboard or on a fret board.

Notice that there are two color slices that are red separated by a blue slice. These two slices are C major and a minor, and D major and b minor. These two red slices are across from two adjoined color red slices called enharmonics--Keys notated differently on the staff, but voiced identically .These are also half-step tones from their color coordinates.

In addition, there are two color slices that are blue separated by a red slice. These two slices are F major and d minor, and G major and e minor. These two blue slices are opposite or across the “...Wheel™” from adjoined color blue slices called enharmonics—Keys notated differently on the staff, but voiced identically. These are also half-step tones from their color coordinates.