Reference: Fataawa al-Lajnah ad-Daa.imah lil-Buhooth al-‘Ilmiyyah wal-Iftaa., – Volume 6, Page 316, Question 11 of Fatwa No.6391
Fataawa tata’allaq bi-Jamaa’ah al-Masjid: Question 30, Page 29
Question: What is the ruling regarding drawing lines on the floor or prayer carpet in the masjid in order to systematically incorporate the rows, keeping in mind that the direction of the qiblah is off-line a little?
Response: There is no harm in this, and if they prayed like this without any lines, then there is no harm [in that either], since there is no harm in being off-line [towards the qiblah] a little.
And with Allaah lies all success and may Allaah send prayers and salutations upon our Prophet Muhammad (sal-Allaahu `alayhi wa sallam) and his family and his companions.