Is there a better way of automating pitch changes of repeated phrases

[Pekay]

Hello, I have been trying to set some simple warm-up exercise type as an
exercise in understanding how to use Lilypond in a concise manner.

Variables are a nice way of doing a lot of repetitive things, however I cannot
seem to be able to find an easy way to take a simple phrase, repeat it but then
keep repeating it half a tone lower (or higher) in subsequent bars.

What I am forced to do is set a different transposition command after each
variable. I get the result, but wondered if there a more elegant manner.

I hope you don't mind, but I shall paste a snippet here of the kind of thing I
am trying to achieve.

% Warm Up Exercises

\version "2.12.2"

PractOne = {g'-1( c') g'( c'')}

\score {

{

\PractOne

\transpose c b,

\PractOne

\slurDown

\transpose c bes,

\PractOne

\transpose c a,

\PractOne

\transpose c aes,

\breathe

\PractOne

\transpose c g,

\PractOne

\transpose c ges,

\PractOne

\breathe


}

}

As you can see I am using a very crude method of transposing each bar down half
a tone. I was hoping that there was some kind of 'incremental' type statement or
is this the best/only way to do what I am trying to achieve?

Thank you for your time.

P