Translation of the verse 30 from Surah Al-Mursalat : Number of verses 50 - - page 581 - Part 29.
"Depart you to a shadow (of Hell-fire smoke ascending) in three columns,
Proceed to a shadow [of smoke] having three columns
(77:30) proceed towards the three-pronged shadow, *18
*18) "Shadow": shadow of smoke; "three branches": because when a big smoke arises it is divided into several parts at the top.
Source : Al-Mursalat Verse 30: Proceed to a shadow [of smoke] having three columns