writing a pattern

[AH1OZ]

I was wondering how you would write this - looking for the most comprehensible, yet simplest way...

my pattern (shawl) has 4 basic rows

row 1 and 3 has a specific sequence that is repeated
row 2 and 4 are simply purls

I am going to write that all the even rows are purls... but its the repeat rows that I need help with

the pattern looks something like this (there are a few starter rows and then the lace begins)

row 1: k, yo, *lace pattern*, k, *lace*, yo, k
row 3: k, yo, *lace*, k3, *lace*, yo, k

each time the lace repeat is increased by 1

so the row 1-4 you simply knit as is
row 5-8 you repeat the lace twice
row 9-12 you repeat the lace 3 times

so how would i write this?

would i write *lace* rep once (or twice or three times) each row?

or could I write 2(lace), 3(lace)? this one is more mathematical - make me think of my calculus days, but i don't know if it would be translated with all knitters

or could I just write a note at the beginning of the pattern saying that an additional repeat is added every 4 rows?