I assume you meant "aebdc@" in your odd example. If so, then you can repeatedly remove the first and last characters from the input string, adding them to the output string in that order, until the length of the remaining string is less than 2.
Then, if there's a character remaining at the end (length is 1, not 0) then append it to the end of your output string, followed by a '@'.
It's been 15+ years since I've done anything at all in VB6, and I don't remember the syntax well enough to offer a working code snippet, but that idea will work with any language that has strings with concatenation and a substring function or method.