When the Prophet (ﷺ) observed I’tikaf, his bedding would be spread for him, or his bed would be placed there for him, behind the Pillar of Repentance.
Sunan Ibn Majah Book 7, Hadith 137
← Previous Hadith The Messenger of Allah (ﷺ) used to spend the last ten days of Ramadan in I’tikaf. Nafi' said: " Abdullah bin 'Umar showed me the place where the Messenger of Allah (ﷺ) used to observe I'tikaf."

Sunan Ibn Majah Book 7, Hadith 136 Next Hadith → The Messenger of Allah (ﷺ) observed I’tifak in a Turkish tent, over the door of which was a piece of reed matting. He pushed the mat aside, then he put his head out and spoke to the people.

Sunan Ibn Majah Book 7, Hadith 138