The formula “one plus one is one” is here essential for this to work. The different cases, upper and lower is dependent on one another. To give us clarity they have to work together, to be like one the upper and lower cases must work together.
Expedition One works best in InDesign or equivalent software.
How to use it: write your text in lower case, copy the text frame and ”Paste in Place”, change your lower case text to upper case (you do that under top menu-type-change case-). Change colour if you want to and maybe change the blending mode in the effects window to "multiply" makes it even more sparkling.
On numbers and ampersand for example, you have to use the glyph window in InDesign to find their second half.