script for a 3 line paragraph

i would like to ask how to make a script that in evry 3 lines of my paragraph(below) it would appear like this:

$ cat myparagraph
this is line 1
this is line 2
this is line3
this is line 4
this is 5
this 6
this is 7
this 8

$ cat myparagraphnew

this is line 1
this is line 2
this is line3

this is line 4
this is 5
this 6

this is 7
this 8

awk '!( NR  % 3 ) {$0 = $0"\n"} 1' myparagraph > myparagraphnew

thanks dude ur so great