line1
line2
line3
line4
line5
line6
line7

(progn
  (add-text-properties 12 13 '(invisible t))
  (add-text-properties 18 19 '(invisible t))
  (add-text-properties 24 25 '(invisible t))
  (add-text-properties 30 31 '(invisible t))
  (setq line-move-ignore-invisible nil))