Abdullah bin Abbas reported,

Regarding "It throws up sparks" [Mursalat 77:32], we used to take a piece of wood three cubits long or more and set it aside for the winter, and we called it qasr.As for "as if they were yellow camels" [Mursalat 77:33], these are the cables of ships, bundled together until they are as thick as a man's waist.

Azami 13663

Sahih

عن ابن عباس

{ترمى بشرر} كنا نعمد إلى الخشبة ثلاثة أذرع أو فوق ذلك، فنرفعه للشتاء، فنسميه القصر، {كأنه جملت صفر} حبال السفن، تجمع حتى تكون كأوساط الرجال.

الأعظمي 13663صحيح
Contents
Reference
Commentary
Ayat
Collection
Jami al-Kamil
Book
Tafsir of the great Quran
Chapter
Tafsir of Surah Mursalat
Section
His saying, "Proceed to that which you used to deny. Proceed to a shadow of three columns, neither shading nor availing against the flame. Indeed, it throws sparks like castles, as if they were yellow camels"
Numbering
Jami al-Kamil 13663 (2nd edition)
Azami 13663