Write a program or function that takes in a nonempty single-line string. The string will either be zero or more spaces followed by one period (a particle), such as . or ., or the string will be a sequence of one or more alternating forward and back slashes (a wave) that could start with either one, such as \ or /\/ or \/\/\/\/\/\/.
In either case, propagate the particle/wave to the right by one unit.
Specifically, in the particle case, insert a space before the ., moving it one place to the right, then output the resulting string. For example:
. → .
. → .
. → .
. → .
. → .
. → .
. → .
. → .
In the wave case, append either / or \ appropriately so the wave keeps alternating and it's length increases by one, then output the resulting string. For example:
/ → /\
\ → \/
/\ → /\/
\/ → \/\
/\/ → /\/\
\/\ → \/\/
/\/\ → /\/\/
\/\/ → \/\/\
In either case, the output may not have trailing spaces but an optional trailing newline is allowed.
The shortest code in bytes wins.
